I. Genes found on the same chromosome = linked genes

Size: px
Start display at page:

Download "I. Genes found on the same chromosome = linked genes"

Transcription

1 Genetic recombination in Eukaryotes: crossing over, part 1 I. Genes found on the same chromosome = linked genes II. III. Linkage and crossing over Crossing over & chromosome mapping I. Genes found on the same chromosome = linked genes Conflicting cytological evidence, only a few dozen chromosomes/individual so must be several genes per chromosome Testcross experiments revealed Conclusion: Genes assort independently if they are on different chromosomes but show linkage if they are on the same chromosome. 1

2 If a testcross is done and the genes are on separate chromosomes: Aa/Bb x aa/bb 2 genes, located on different chromosomes, will segregate independently. 2

3 Chromosome is the unit of transmission, not the gene Linkage = two or more genes located on the same chromosome Linked genes are not free to undergo independent assortment Instead, the alleles at all loci of one chromosome, should in theory, be transmitted as a unit during gamete formation. When two genes are compeletely linked, no crossing over occurs therefore, 3

4 II. Linkage and crossing over A. Crossing over breakage and rejoining process between Crossing over produces The % of recombinant gametes varies, dependent upon location of the loci. The closer the genes are, C.O. Breakage and rejoining process between two homologous non-sister chromatids, keep in mind: 4

5 Recombination Frequency (RF) = the # of recombinants/total progeny B. Recombination Frequency (RF), unlinked genes v. linked genes 1). In the case of unlinked genes, independent assortment holds true: Testcross: Heterozygous x homozygous mutant AaBb x aabb Offspring: So from a cross resulting in 100 progeny we would see 25 individuals from each genotype. the # of recombinants 5

6 2). In the case of linked genes, there is no independent assortment Testcross: Heterozygous x homozygous mutant AaBb x aabb Offspring: AaBb, aabb, Aabb, aabb So from a cross resulting in 100 progeny we would see a lot more of these two genotypes when compared to the recombinants: Crossing between adjacent non sister chromatids generates recombinants The two chromatids not involved in the exchange result in non-parental gametes 6

7 We can compare the RF to what one would expect with independent assortment RF Range Recombination by Crossing Over points to keep in mind: 1. CO s can occur between any two nonsister chromatids 2. If there is NO crossing over, only parental types will be observed 3. If there IS crossing over, RF will increase up to 50% 4. when the loci of two linked genes are very far apart, the RF approaches 50%, 1:1:1:1 ratio observed, thus transmission of the linked genes is indistinguishable from that of two unlinked genes 7

8 Morgan noted the proportion of recombinant progeny varied depending on which linked genes were being examined Testcross F1 results: pr + pr vg + vg x pr pr vg vg pr + vg pr vg 1195 pr + vg 151 pr vg y + y w + w x yy ww y w 43 y + w 2146 y w y + w + 22 As Morgan studied more linked genes, he saw that the proportion of recombinant progeny varied considerably. III. Chromosome mapping determined by analyzing Drosophila crosses Morgan hypothesized that variations in RF might indicate the actual distances separating genes on the chromosomes. Sturtevant (Morgan s student) compiled data on recombination between genes in Drosophila test crosses He found that the closer the two linked genes, the lower the recombination frequency- thus RF may be correlated with the map distance between two loci on a chromosome Alfred Sturtevant 8

9 A. Linkage Maps derived by Sturtevant Linkage of genes can be represented in the form of a genetic map, which shows the linear order of genes along a chromosome. The % recombinant offspring is correlated w/the distance between the two genes, thus the degree of crossing over between any two loci on a single chromosome is proportional to the distance between them, known as the interlocus distance Variations in recombination frequency indicate B. Map Units Map Unit (m.u.) = the distance between genes for which one product of meiosis out of 100 is recombinant [RF of 1% = 1 m.u. or 1 cm] e.g. if RF 12% between A & B, and 28% between B & C: A B C 9

10 Linkage map of Drosophila 4 linkage groups identified 10

11 F1: F2 males females F1 F2 males females 11

12 A plant of genotype: A B a b Is test-crossed to a b a b If the two loci are 10 m.u. apart, what proportion of progeny will be A B / a b? In the garden pea, orange pods (orp) are recessive to normal pods (Orp), and sensitivity to pea mosaic virus (mo) is recessive to resistance to the virus (Mo). A plant with orange pods and sensitivity is crossed to a true-breeding plant with normal pods and resistance. The F1 plants were then test-crossed to plants with orange pods and sensitivity. The following results were obtained: 160 orange pods/sensitive 165 normal pods/resistant 36 orange pods/resistant 39 normal pods/sensitive calculate the map distance between the two genes 12

13 C. Mapping multiple genes Threepoint mapping & Alfred s research Hypothesis = when multiple genes are located on the same chromosome, the distance between the genes can be estimated from the proportion of recombinant offspring. A. Sturtevant s First Genetic Map The linear order of these genes can be determined using testcross data Examined 5 different genes: y, w, v, m, r All alleles were found to be recessive and X linked. Crossed the double heterozygote female with hemizygous male recessive for the same alleles. Example: y+y w+w x yw y+w+ yw y+w yw+ RF = 214/21,736 = w+w r+r x wr w+r+ wr w+r wr+ RF = 2,062/6116 =

14 genes are arranged on the chromosome in a linear order- which can be determined The Complete Data: Alleles y and w y and v y and r y and m w and v w and r w and m v and r w and m # R./total# 214/21,736 1,464/4, / / /1,584 2,062/ /898 17/ /405 RF 1% 32.2% 35.5% 37.5% 29.7% 33.7% 45.2% 3% 26.9% 14

15 y-w = 1 m.u. v-r = 3 m.u. y-m = 37.5 m.u. w-r = 33.7 m.u. w-v = 29.7 m.u. Eukaryotic linkage, part 2 I. Three-point mapping to determine genetic maps A. Multiple cross-overs B. How to: analyzing the 3 pt testcross C. Mapping the results D. The accuracy of mapping E. Mitotic recombination and Sister Chromatid Exhanges II. Genetic mapping in haploid eukaryotes A. Ordered tetrad analysis B. Unordered tetrad analysis 15

16 I. Three-point mapping in Drosophila to determine genetic maps We can map 3 or more linked genes in a single cross, provided the following are true: The genotype of the organism producing crossover gametes must be heterozygous for all loci under consideration Offspring sample size must be high enough to recover a representative sample of all crossover classes DCOs (double crossovers) double exchanges of genetic material in two regions (RI & RII) RI RII Probability of a single crossover occurring between two loci is directly related to the distance separating the loci in the case of a DCO, two separate and independent crossovers must occur simultaneously. 16

17 three-point testcross for mapping Cross two true-breeding strains that differ with regard to three alleles to obtain F1 individuals that are heterozygous for all three alleles: y + y, w + w, ec + ec Perform a testcross by mating the F1 female to males that are homozygous recessive for all three alleles Results in 8 phenotypic classes (2 3 ) FI female: (heterozygous for 3 genes) her possible gametes: y w ec y+ w+ ec+ y w ec+ y w+ ec y w+ ec+ y+ w ec y+ w+ ec y+ w ec+ Because the F 2 phenotypes complement each other (i.e., one is wild type and the other is mutant for all three genes), they are called reciprocal classes of phenotypes. The distance between two genes in a three-point cross is equal to the percentage of all detectable exchanges occurring between them and includes all single and double crossovers. 17

18 How to: analyzing the 3 pt testcross Collect data from the F2 generation. Parental types (usually the two highest # s) Non-Parentals (recombinants) Double Crossovers (two lowest # s) Single Crossovers (two are RI, two are RII) Determine the gene order based upon the DCOs Calculate the RF for each region to determine the map distance between genes (#recombinants/total x 100) P: v + v +, cvcv, ctct x vv, cv + cv +, ct + ct + Testcross: v + v, cv + cv, ct + ct x vv, cvcv, ctct Phenotype v cv + ct + v + cv ct 592 v cv ct + 45 v + cv + ct 40 v cv ct 89 v + cv + ct + 94 v cv + ct 3 v + cv ct + 5 # offspring

19 Parental input Possible output t Only the first possibility is compatible with the data. Example: bb, prpr, vgvg x b + b, + pr + pr, + vg + vg + F1: b + b pr + pr vg + vg testcross: b + b pr + pr vg + vg x bb prpr vgvg Phenotype b + pr + vg + b pr vg b + pr vg 30 b pr + vg + 28 b + pr + vg 61 b pr vg + 60 b + pr vg + 2 b pr + vg # observed Distance between b & pr = Distance between pr & vg = 19

20 Mapping the results: The eye color gene must be in the middle. This order of genes is confirmed by the pattern of traits found in the double crossovers. Double crossover data b + pr vg + 2 b pr + vg 1 D. The accuracy of mapping: Interference Interference = When a crossover in one region affects the likelihood of there being a crossover in an adjacent region Expected frequency of DCOs DCOs rare between segments that are very short If crossovers in the 2 regions are independent, then: frequency of double recombinants = product of the recombinant frequencies in the adjacent regions Expected DCOs = x = x 1,005 = 7.5 Coefficient of coincidence (c.o.c) Observed/expected double recombinants 1 3/7.5 = 0.4 I = 1-c.o.c 20

21 Step by step summary: 1. Calculate the RF for each pair of genes 2. Draw the linkage map 3. Determine the double recombinants 4. Calculate the Frequency & # of double recombinants expected if there is no interference 5. Calculate Interference Problem: Vermilion eyes are recessive to normal, miniature wings are recessive to long wings, and sable body is recessive to gray body. A cross was made between a heterozygous female for all three genes and a homozygous recessive male. Data: 1,320 vermilion eyes, miniature wings, sable body 1,346 red eyes, long wings, gray body 102 vermilion eyes, miniature wings, gray body 90 red eyes, long wings, sable body 42 vermilion eyes, long wings, gray body 48 red eyes, miniature wings, sable body 2 vermilion eyes, long wings, sable body 1 red eyes, miniature wings, gray body A. Determine the gene order & calculate the map distance between the three genes B. Calculate interference 21

22 E. Mitotic recombination and Sister Chromatid Exhanges Mitotic recombination = crossing over that occurs during mitosis (it does happen, in often in Drosophila & fungi also in humans & mice) It is likely that the recombinational repair of DNA lesions occurs preferentially by sister chromatid exchanges that have no genetic consequences Those between non-sister chromatids producemutant patches in female flies = twin spot SCE s don t produce new allelic combinations, but may be involved in repairing DNA lesions II. Genetic mapping in haploid eukaryotes Fungi haploid (n) multicellular organisms that can reproduce asexually to create a diploid zygote Diploid zygote proceeds through meiosis to produce four haploid spores = ascospores 22

23 23

24 Group of four spores is known as a tetrad In some species meiosis is followed by mitosis to produce eight cells known as an octad. Ascus = sac that contains the tetrad/octad Can do an ordered tetrad analysis because the 8 cells reflect the sequence of formation what s the fun in fungi? They are haploid They produce large # s of progeny They have short life cycles Can make direct observations on the behavior of genes during meiosis, can examine cross-overs, can map centromeres Chlamydomonas Neurospora 24

25 A. Ordered tetrad analysis: Linear tetrad analysis can be used to map distance between a gene and the centromere. 1). FDS PATTERN: 2) SDS PATTERN: a) 2:2:2:2 b) 2:4:2 segregate until the 2 nd meitotic division is complete! 25

26 Calculating map distance w/ ordered tetrads mapping the centromere - % of SDS or M2 asci can be used to calculate the map distance between the centromere & the gene of interest Map distance = B. Unordered tetrad analysis can be used to map genes in dihybrid crosses, Spores are randomly arranged Haploid cell AB x ab Haploid cell Aa Bb Diploid zygote meiosis AB AB AB Ab Ab Ab ab ab ab ab ab ab Parental ditype Tetratype Nonparental ditype 26

27 When two genes are located on different chromosomes: 27

28 When two genes are located on the same chromosome: Map distance = (1/2) ([TT] + 3[NPD]) + 4 [NPD] / total x 100 If the # of parentals = nonparentals, the two are unlinked If there are TT s, CO s have occurred, if there are NPDs then DCO s occurred. The following spore arrangements were obtained from tetrads in a cross between Neurospora strain com val (c v) and a wild type strain (+ +). Only 1 member of each pair of spores is shown. Spore pair Ascus composition 1-2 cv c+ cv +v cv 3-4 cv c+ c+ c+ +v v +v cv c v Number: What can you conclude about linkage? 35 PD 36 NPD 30 TT PD = NPD, genes not linked 28

and the Mapping of Genes on Chromosomes

and the Mapping of Genes on Chromosomes Lecture 5 Linkage, Recombination, and the Mapping of Genes on Chromosomes http://lms.ls.ntou.edu.tw/course/136 1 Outline Part 1 Linkage and meiotic recombination Genes linked together on the same chromosome

More information

2. The Law of Independent Assortment Members of one pair of genes (alleles) segregate independently of members of other pairs.

2. The Law of Independent Assortment Members of one pair of genes (alleles) segregate independently of members of other pairs. 1. The Law of Segregation: Genes exist in pairs and alleles segregate from each other during gamete formation, into equal numbers of gametes. Progeny obtain one determinant from each parent. 2. The Law

More information

5 GENETIC LINKAGE AND MAPPING

5 GENETIC LINKAGE AND MAPPING 5 GENETIC LINKAGE AND MAPPING 5.1 Genetic Linkage So far, we have considered traits that are affected by one or two genes, and if there are two genes, we have assumed that they assort independently. However,

More information

CHAPTER 6 GENETIC RECOMBINATION IN EUKARYOTES + CHAP[TER 14, PAGES 456-459)

CHAPTER 6 GENETIC RECOMBINATION IN EUKARYOTES + CHAP[TER 14, PAGES 456-459) CHAPTER 6 GENETIC RECOMBINATION IN EUKARYOTES + CHAP[TER 14, PAGES 456-459) Questions to be addressed: 1. How can we predict the inheritance patterns of more than one gene? 2. How does the position of

More information

11.4 Meiosis. Lesson Objectives. Lesson Summary

11.4 Meiosis. Lesson Objectives. Lesson Summary 11.4 Meiosis Lesson Objectives Contrast the number of chromosomes in body cells and in gametes. Summarize the events of meiosis. Contrast meiosis and mitosis. Describe how alleles from different genes

More information

Chapter 9 Patterns of Inheritance

Chapter 9 Patterns of Inheritance Bio 100 Patterns of Inheritance 1 Chapter 9 Patterns of Inheritance Modern genetics began with Gregor Mendel s quantitative experiments with pea plants History of Heredity Blending theory of heredity -

More information

Name: Class: Date: ID: A

Name: Class: Date: ID: A Name: Class: _ Date: _ Meiosis Quiz 1. (1 point) A kidney cell is an example of which type of cell? a. sex cell b. germ cell c. somatic cell d. haploid cell 2. (1 point) How many chromosomes are in a human

More information

Meiosis and Sexual Life Cycles

Meiosis and Sexual Life Cycles Meiosis and Sexual Life Cycles Chapter 13 1 Ojectives Distinguish between the following terms: somatic cell and gamete; autosome and sex chromosomes; haploid and diploid. List the phases of meiosis I and

More information

5. The cells of a multicellular organism, other than gametes and the germ cells from which it develops, are known as

5. The cells of a multicellular organism, other than gametes and the germ cells from which it develops, are known as 1. True or false? The chi square statistical test is used to determine how well the observed genetic data agree with the expectations derived from a hypothesis. True 2. True or false? Chromosomes in prokaryotic

More information

CHAPTER 4 STURTEVANT: THE FIRST GENETIC MAP: DROSOPHILA X CHROMOSOME LINKED GENES MAY BE MAPPED BY THREE-FACTOR TEST CROSSES STURTEVANT S EXPERIMENT

CHAPTER 4 STURTEVANT: THE FIRST GENETIC MAP: DROSOPHILA X CHROMOSOME LINKED GENES MAY BE MAPPED BY THREE-FACTOR TEST CROSSES STURTEVANT S EXPERIMENT CHAPTER 4 STURTEVANT: THE FIRST GENETIC MAP: DROSOPHILA X CHROMOSOME In 1913, Alfred Sturtevant drew a logical conclusion from Morgan s theories of crossing-over, suggesting that the information gained

More information

Chapter 13: Meiosis and Sexual Life Cycles

Chapter 13: Meiosis and Sexual Life Cycles Name Period Chapter 13: Meiosis and Sexual Life Cycles Concept 13.1 Offspring acquire genes from parents by inheriting chromosomes 1. Let s begin with a review of several terms that you may already know.

More information

Chromosomes, Mapping, and the Meiosis Inheritance Connection

Chromosomes, Mapping, and the Meiosis Inheritance Connection Chromosomes, Mapping, and the Meiosis Inheritance Connection Carl Correns 1900 Chapter 13 First suggests central role for chromosomes Rediscovery of Mendel s work Walter Sutton 1902 Chromosomal theory

More information

CLASSICAL GENETICS: TETRAD ANALYSIS and RECOMBINATION. References

CLASSICAL GENETICS: TETRAD ANALYSIS and RECOMBINATION. References CLASSICAL GENETICS: TETRAD ANALYSIS and RECOMBINATION References 1. Perkins, D.D. (1962) Crossing-over and interference in a multiply marked chromosome arm of Neurosopora. Genetics 47, 1253-1274. Classic

More information

Lecture 2: Mitosis and meiosis

Lecture 2: Mitosis and meiosis Lecture 2: Mitosis and meiosis 1. Chromosomes 2. Diploid life cycle 3. Cell cycle 4. Mitosis 5. Meiosis 6. Parallel behavior of genes and chromosomes Basic morphology of chromosomes telomere short arm

More information

Exam 1. CSS/Hort 430. 2008 All questions worth 2 points

Exam 1. CSS/Hort 430. 2008 All questions worth 2 points Exam 1. CSS/Hort 430. 2008 All questions worth 2 points 1. A general definition of plants is they are eukaryotic, multi-cellular organisms and are usually photosynthetic. In this definition, eukaryotic

More information

The correct answer is c A. Answer a is incorrect. The white-eye gene must be recessive since heterozygous females have red eyes.

The correct answer is c A. Answer a is incorrect. The white-eye gene must be recessive since heterozygous females have red eyes. 1. Why is the white-eye phenotype always observed in males carrying the white-eye allele? a. Because the trait is dominant b. Because the trait is recessive c. Because the allele is located on the X chromosome

More information

Chapter 13: Meiosis and Sexual Life Cycles

Chapter 13: Meiosis and Sexual Life Cycles Name Period Concept 13.1 Offspring acquire genes from parents by inheriting chromosomes 1. Let s begin with a review of several terms that you may already know. Define: gene locus gamete male gamete female

More information

7.03 Fall 2004 PSets w/keys 1 of 112

7.03 Fall 2004 PSets w/keys 1 of 112 7.03 Fall 2004 PSets w/keys 1 of 112 7.03 Problem Set 1 Due before 5 PM on Thursday, September 23, 2004 Hand in answers to the appropriate slot in the box outside of 68-120. Late problem Sets will NOT

More information

Bio EOC Topics for Cell Reproduction: Bio EOC Questions for Cell Reproduction:

Bio EOC Topics for Cell Reproduction: Bio EOC Questions for Cell Reproduction: Bio EOC Topics for Cell Reproduction: Asexual vs. sexual reproduction Mitosis steps, diagrams, purpose o Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis Meiosis steps, diagrams, purpose

More information

Biology 160 Lab Module 10 Meiosis Activity & Mendelian Genetics

Biology 160 Lab Module 10 Meiosis Activity & Mendelian Genetics Name Biology 160 Lab Module 10 Meiosis Activity & Mendelian Genetics Introduction During your lifetime you have grown from a single celled zygote into an organism made up of trillions of cells. The vast

More information

Practice Problems 4. (a) 19. (b) 36. (c) 17

Practice Problems 4. (a) 19. (b) 36. (c) 17 Chapter 10 Practice Problems Practice Problems 4 1. The diploid chromosome number in a variety of chrysanthemum is 18. What would you call varieties with the following chromosome numbers? (a) 19 (b) 36

More information

2. is a process of nuclear division in which the number of chromosomes in certain cells is halved during gamete formation.

2. is a process of nuclear division in which the number of chromosomes in certain cells is halved during gamete formation. Meiosis 1. P. J. van Beneden proposed that an egg and a sperm, each containing half the complement of chromosomes found in somatic cells, fuse to produce a single cell called a. 2. is a process of nuclear

More information

List, describe, diagram, and identify the stages of meiosis.

List, describe, diagram, and identify the stages of meiosis. Meiosis and Sexual Life Cycles In this topic we will examine a second type of cell division used by eukaryotic cells: meiosis. In addition, we will see how the 2 types of eukaryotic cell division, mitosis

More information

A and B are not absolutely linked. They could be far enough apart on the chromosome that they assort independently.

A and B are not absolutely linked. They could be far enough apart on the chromosome that they assort independently. Name Section 7.014 Problem Set 5 Please print out this problem set and record your answers on the printed copy. Answers to this problem set are to be turned in to the box outside 68-120 by 5:00pm on Friday

More information

1. Why is mitosis alone insufficient for the life cycle of sexually reproducing eukaryotes?

1. Why is mitosis alone insufficient for the life cycle of sexually reproducing eukaryotes? Chapter 13: Meiosis and Sexual Life Cycles 1. Why is mitosis alone insufficient for the life cycle of sexually reproducing eukaryotes? 2. Define: gamete zygote meiosis homologous chromosomes diploid haploid

More information

INTRODUCTION TO GENETICS USING TOBACCO (Nicotiana tabacum) SEEDLINGS

INTRODUCTION TO GENETICS USING TOBACCO (Nicotiana tabacum) SEEDLINGS INTRODUCTION TO GENETICS USING TOBACCO (Nicotiana tabacum) SEEDLINGS By Dr. Susan Petro Based on a lab by Dr. Elaine Winshell Nicotiana tabacum Objectives To apply Mendel s Law of Segregation To use Punnett

More information

Heredity - Patterns of Inheritance

Heredity - Patterns of Inheritance Heredity - Patterns of Inheritance Genes and Alleles A. Genes 1. A sequence of nucleotides that codes for a special functional product a. Transfer RNA b. Enzyme c. Structural protein d. Pigments 2. Genes

More information

Biology 1406 Exam 4 Notes Cell Division and Genetics Ch. 8, 9

Biology 1406 Exam 4 Notes Cell Division and Genetics Ch. 8, 9 Biology 1406 Exam 4 Notes Cell Division and Genetics Ch. 8, 9 Ch. 8 Cell Division Cells divide to produce new cells must pass genetic information to new cells - What process of DNA allows this? Two types

More information

CCR Biology - Chapter 7 Practice Test - Summer 2012

CCR Biology - Chapter 7 Practice Test - Summer 2012 Name: Class: Date: CCR Biology - Chapter 7 Practice Test - Summer 2012 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A person who has a disorder caused

More information

c. Law of Independent Assortment: Alleles separate and do not have an effect on another allele.

c. Law of Independent Assortment: Alleles separate and do not have an effect on another allele. Level Genetics Review KEY Describe the 3 laws that Gregor Mendel established after working with pea plants. a. Law of Dominance: states that the effect of a recessive allele is not observed when a dominant

More information

Name: 4. A typical phenotypic ratio for a dihybrid cross is a) 9:1 b) 3:4 c) 9:3:3:1 d) 1:2:1:2:1 e) 6:3:3:6

Name: 4. A typical phenotypic ratio for a dihybrid cross is a) 9:1 b) 3:4 c) 9:3:3:1 d) 1:2:1:2:1 e) 6:3:3:6 Name: Multiple-choice section Choose the answer which best completes each of the following statements or answers the following questions and so make your tutor happy! 1. Which of the following conclusions

More information

CELL DIVISION: MITOSIS AND MEIOSIS

CELL DIVISION: MITOSIS AND MEIOSIS CELL DIVISION: MITOSIS AND MEIOSIS How do eukaryotic cells divide to produce genetically identical cells or to produce gametes with half the normal DNA? BACKGROUND One of the characteristics of living

More information

Chapter 8 Cell division. Review

Chapter 8 Cell division. Review Chapter 8 Cell division Mitosis/Meiosis Review This spot that holds the 2 chromatid copies together is called a centromere The phase of the cell cycle in which cells stop dividing all together. G 0 Cell

More information

Mendelian Genetics. I. Background

Mendelian Genetics. I. Background Mendelian Genetics Objectives 1. To understand the Principles of Segregation and Independent Assortment. 2. To understand how Mendel s principles can explain transmission of characters from one generation

More information

Mitosis & Meiosis. Bio 103 Lecture Dr. Largen

Mitosis & Meiosis. Bio 103 Lecture Dr. Largen 1 Mitosis & Meiosis Bio 103 Lecture Dr. Largen 2 Cells arise only from preexisting cells all cells come from cells perpetuation of life based on reproduction of cells referred to as cell division 3 Cells

More information

Heredity. Sarah crosses a homozygous white flower and a homozygous purple flower. The cross results in all purple flowers.

Heredity. Sarah crosses a homozygous white flower and a homozygous purple flower. The cross results in all purple flowers. Heredity 1. Sarah is doing an experiment on pea plants. She is studying the color of the pea plants. Sarah has noticed that many pea plants have purple flowers and many have white flowers. Sarah crosses

More information

STUDENT ID NUMBER, LAST NAME,

STUDENT ID NUMBER, LAST NAME, EBIO 1210: General Biology 1 Name Exam 3 June 25, 2013 To receive credit for this exam, you MUST bubble in your STUDENT ID NUMBER, LAST NAME, and FIRST NAME No. 2 pencils only You may keep this exam to

More information

Name Per: Date: Cell Division/Mitosis/Meiosis Test Study Guide. 1. Explain why cells are small instead of large. (Reference surface area and volume).

Name Per: Date: Cell Division/Mitosis/Meiosis Test Study Guide. 1. Explain why cells are small instead of large. (Reference surface area and volume). Name Per: Date: Cell Division/Mitosis/Meiosis Test Study Guide 1. Explain why cells are small instead of large. (Reference surface area and volume). 2. What are the two main phases of the cell cycle? 3.

More information

(1-p) 2. p(1-p) From the table, frequency of DpyUnc = ¼ (p^2) = #DpyUnc = p^2 = 0.0004 ¼(1-p)^2 + ½(1-p)p + ¼(p^2) #Dpy + #DpyUnc

(1-p) 2. p(1-p) From the table, frequency of DpyUnc = ¼ (p^2) = #DpyUnc = p^2 = 0.0004 ¼(1-p)^2 + ½(1-p)p + ¼(p^2) #Dpy + #DpyUnc Advanced genetics Kornfeld problem set_key 1A (5 points) Brenner employed 2-factor and 3-factor crosses with the mutants isolated from his screen, and visually assayed for recombination events between

More information

HEREDITY (B) In domestic cats, the gene for Tabby stripes (T) is dominant over the gene for no stripes (t)

HEREDITY (B) In domestic cats, the gene for Tabby stripes (T) is dominant over the gene for no stripes (t) GENETIC CROSSES In minks, a single gene controls coat color. The allele for a brown (B) coat is dominant to the allele for silver-blue (b) coats. 1. A homozygous brown mink was crossed with a silverblue

More information

BIOL100 Laboratory Assignment 4: Mitosis and Meiosis. Name:

BIOL100 Laboratory Assignment 4: Mitosis and Meiosis. Name: BIOL100 Laboratory Assignment 4: Mitosis and Meiosis Name: Laboratory Objectives After completing this lab topic, you should be able to: 1. Describe the activities of chromosomes and microtubules in the

More information

Eukaryotic Cells and the Cell Cycle

Eukaryotic Cells and the Cell Cycle Eukaryotic Cells and the Cell Cycle Mitosis, Meiosis, & Fertilization Learning Goals: After completing this laboratory exercise you will be able to: 1. Identify the stages of the cell cycle. 2. Follow

More information

LAB 8 EUKARYOTIC CELL DIVISION: MITOSIS AND MEIOSIS

LAB 8 EUKARYOTIC CELL DIVISION: MITOSIS AND MEIOSIS LAB 8 EUKARYOTIC CELL DIVISION: MITOSIS AND MEIOSIS Los Angeles Mission College Biology 3 Name: Date: INTRODUCTION BINARY FISSION: Prokaryotic cells (bacteria) reproduce asexually by binary fission. Bacterial

More information

The cell cycle, mitosis and meiosis

The cell cycle, mitosis and meiosis The cell cycle, mitosis and meiosis Learning objective This learning material is about the life cycle of a cell and the series of stages by which genetic materials are duplicated and partitioned to produce

More information

LAB EXERCISE: Mitosis and Meiosis

LAB EXERCISE: Mitosis and Meiosis LAB EXERCISE: Mitosis and Meiosis Laboratory Objectives After completing this lab topic, you should be able to: 1. Describe the activities of chromosomes and microtubules in the cell cycle, including all

More information

GENETIC CROSSES. Monohybrid Crosses

GENETIC CROSSES. Monohybrid Crosses GENETIC CROSSES Monohybrid Crosses Objectives Explain the difference between genotype and phenotype Explain the difference between homozygous and heterozygous Explain how probability is used to predict

More information

Mendelian Inheritance & Probability

Mendelian Inheritance & Probability Mendelian Inheritance & Probability (CHAPTER 2- Brooker Text) January 31 & Feb 2, 2006 BIO 184 Dr. Tom Peavy Problem Solving TtYy x ttyy What is the expected phenotypic ratio among offspring? Tt RR x Tt

More information

Genetics Lecture Notes 7.03 2005. Lectures 1 2

Genetics Lecture Notes 7.03 2005. Lectures 1 2 Genetics Lecture Notes 7.03 2005 Lectures 1 2 Lecture 1 We will begin this course with the question: What is a gene? This question will take us four lectures to answer because there are actually several

More information

Complex Inheritance. Mendel observed monogenic traits and no linked genes It s not usually that simple.

Complex Inheritance. Mendel observed monogenic traits and no linked genes It s not usually that simple. Complex Inheritance Mendel observed monogenic traits and no linked genes It s not usually that simple. Other Types of Inheritance Incomplete Dominance The phenotype of the heterozygote is intermediate

More information

Multiple Choice Review Mitosis & Meiosis

Multiple Choice Review Mitosis & Meiosis Multiple Choice Review Mitosis & Meiosis 1. Which of the following accurately describes the one of the major divisions of mitosis? a. During the mitotic phase, cells are performing their primary function

More information

Workshop: Cellular Reproduction via Mitosis & Meiosis

Workshop: Cellular Reproduction via Mitosis & Meiosis Workshop: Cellular Reproduction via Mitosis & Meiosis Introduction In this workshop you will examine how cells divide, including how they partition their genetic material (DNA) between the two resulting

More information

CHROMOSOMES AND INHERITANCE

CHROMOSOMES AND INHERITANCE SECTION 12-1 REVIEW CHROMOSOMES AND INHERITANCE VOCABULARY REVIEW Distinguish between the terms in each of the following pairs of terms. 1. sex chromosome, autosome 2. germ-cell mutation, somatic-cell

More information

Cell Growth and Reproduction Module B, Anchor 1

Cell Growth and Reproduction Module B, Anchor 1 Cell Growth and Reproduction Module B, Anchor 1 Key Concepts: - The larger a cell becomes, the more demands the cell places on its DNA. In addition, a larger cell is less efficient in moving nutrients

More information

CHROMOSOME STRUCTURE CHROMOSOME NUMBERS

CHROMOSOME STRUCTURE CHROMOSOME NUMBERS CHROMOSOME STRUCTURE 1. During nuclear division, the DNA (as chromatin) in a Eukaryotic cell's nucleus is coiled into very tight compact structures called chromosomes. These are rod-shaped structures made

More information

1. You are studying three autosomal recessive mutations in the fruit fly Drosophila

1. You are studying three autosomal recessive mutations in the fruit fly Drosophila 7.03 Exams Archives 1 of 126 Exam Questions from Exam 1 Basic Genetic Tests, Setting up and Analyzing Crosses, and Genetic Mapping 1. You are studying three autosomal recessive mutations in the fruit fly

More information

2 GENETIC DATA ANALYSIS

2 GENETIC DATA ANALYSIS 2.1 Strategies for learning genetics 2 GENETIC DATA ANALYSIS We will begin this lecture by discussing some strategies for learning genetics. Genetics is different from most other biology courses you have

More information

Asexual - in this case, chromosomes come from a single parent. The text makes the point that you are not exact copies of your parents.

Asexual - in this case, chromosomes come from a single parent. The text makes the point that you are not exact copies of your parents. Meiosis The main reason we have meiosis is for sexual reproduction. It mixes up our genes (more on that later). But before we start to investigate this, let's talk a bit about reproduction in general:

More information

Asexual Reproduction in Eukaryotes: Mitosis

Asexual Reproduction in Eukaryotes: Mitosis Asexual Reproduction in Eukaryotes: Mitosis The Argentine band The real thing going on inside their cells Nuclear Genomes and Chromosomes Genome size in bp (or kbp or Mbp or Gbp) = C value S. cerevisiae

More information

Chapter 21 Active Reading Guide The Evolution of Populations

Chapter 21 Active Reading Guide The Evolution of Populations Name: Roksana Korbi AP Biology Chapter 21 Active Reading Guide The Evolution of Populations This chapter begins with the idea that we focused on as we closed Chapter 19: Individuals do not evolve! Populations

More information

BioSci 2200 General Genetics Problem Set 1 Answer Key Introduction and Mitosis/ Meiosis

BioSci 2200 General Genetics Problem Set 1 Answer Key Introduction and Mitosis/ Meiosis BioSci 2200 General Genetics Problem Set 1 Answer Key Introduction and Mitosis/ Meiosis Introduction - Fields of Genetics To answer the following question, review the three traditional subdivisions of

More information

Bio 102 Practice Problems Mendelian Genetics and Extensions

Bio 102 Practice Problems Mendelian Genetics and Extensions Bio 102 Practice Problems Mendelian Genetics and Extensions Short answer (show your work or thinking to get partial credit): 1. In peas, tall is dominant over dwarf. If a plant homozygous for tall is crossed

More information

Biology Final Exam Study Guide: Semester 2

Biology Final Exam Study Guide: Semester 2 Biology Final Exam Study Guide: Semester 2 Questions 1. Scientific method: What does each of these entail? Investigation and Experimentation Problem Hypothesis Methods Results/Data Discussion/Conclusion

More information

1. When new cells are formed through the process of mitosis, the number of chromosomes in the new cells

1. When new cells are formed through the process of mitosis, the number of chromosomes in the new cells Cell Growth and Reproduction 1. When new cells are formed through the process of mitosis, the number of chromosomes in the new cells A. is half of that of the parent cell. B. remains the same as in the

More information

Sexual Reproduction. The specialized cells that are required for sexual reproduction are known as. And come from the process of: GAMETES

Sexual Reproduction. The specialized cells that are required for sexual reproduction are known as. And come from the process of: GAMETES Sexual Reproduction Sexual Reproduction We know all about asexual reproduction 1. Only one parent required. 2. Offspring are identical to parents. 3. The cells that produce the offspring are not usually

More information

AP: LAB 8: THE CHI-SQUARE TEST. Probability, Random Chance, and Genetics

AP: LAB 8: THE CHI-SQUARE TEST. Probability, Random Chance, and Genetics Ms. Foglia Date AP: LAB 8: THE CHI-SQUARE TEST Probability, Random Chance, and Genetics Why do we study random chance and probability at the beginning of a unit on genetics? Genetics is the study of inheritance,

More information

Punnett Square: Monohybird Crosses

Punnett Square: Monohybird Crosses Punnett Squares A Punnett square is a mathematical device used by geneticists to show combinations of gametes and to predict offspring ratios. There are a few fundamental concepts of Punnett squares that

More information

Cell Division. Use Target Reading Skills. This section explains how cells grow and divide.

Cell Division. Use Target Reading Skills. This section explains how cells grow and divide. Cell Processes and Energy Name Date Class Cell Processes and Energy Guided Reading and Study Cell Division This section explains how cells grow and divide. Use Target Reading Skills As you read, make a

More information

BioBoot Camp Genetics

BioBoot Camp Genetics BioBoot Camp Genetics BIO.B.1.2.1 Describe how the process of DNA replication results in the transmission and/or conservation of genetic information DNA Replication is the process of DNA being copied before

More information

Determining Acceptance of the 9:3:3:1 Ratio in Fruit Fly Crosses Using the Chi Squared Test

Determining Acceptance of the 9:3:3:1 Ratio in Fruit Fly Crosses Using the Chi Squared Test Determining Acceptance of the 9:3:3:1 Ratio in Fruit Fly Crosses Using the Chi Squared Test Abstract In this experiment we set out to determine whether or not two different fruit fly crosses fit the 9:3:3:1

More information

Exercise 1: Q: B.1. Answer Cell A: 2 Q: B.3. Answer (a) Somatic (body). CELL CYCLE, CELL DIVISION AND STRUCTURE OF CHROMOSOME. Cell B: 4 Q: B.

Exercise 1: Q: B.1. Answer Cell A: 2 Q: B.3. Answer (a) Somatic (body). CELL CYCLE, CELL DIVISION AND STRUCTURE OF CHROMOSOME. Cell B: 4 Q: B. CELL CYCLE, CELL DIVISION AND STRUCTURE OF CHROMOSOME Exercise 1: Q: B.1 Cell A: 2 Cell B: 4 Q: B.2 (a) - Metaphase. (b) - Telophase. (c) - Prophase. (d) - Anaphase. Q: B.3 (a) Somatic (body). (b) Four.

More information

A trait is a variation of a particular character (e.g. color, height). Traits are passed from parents to offspring through genes.

A trait is a variation of a particular character (e.g. color, height). Traits are passed from parents to offspring through genes. 1 Biology Chapter 10 Study Guide Trait A trait is a variation of a particular character (e.g. color, height). Traits are passed from parents to offspring through genes. Genes Genes are located on chromosomes

More information

Chapter 8: The Cellular Basis of Reproduction and Inheritance

Chapter 8: The Cellular Basis of Reproduction and Inheritance Chapter 8: The Cellular Basis of Reproduction and Inheritance Introduction Stages of an Organism s Life Cycle: Development: All changes that occur from a fertilized egg or an initial cell to an adult organism.

More information

Sex Linkage. Reciprocal Cross. Exceptions 8/26/10

Sex Linkage. Reciprocal Cross. Exceptions 8/26/10 Sex Linkage Reciprocal Cross Organisms that have different sexes can be crossed in two different ways Phenotype A male X Phenotype B female Phenotype B male X Phenotype A female Mendel concluded that reciprocal

More information

Meiosis is a special form of cell division.

Meiosis is a special form of cell division. Page 1 of 6 KEY CONCEPT Meiosis is a special form of cell division. BEFORE, you learned Mitosis produces two genetically identical cells In sexual reproduction, offspring inherit traits from both parents

More information

Chromosomal Basis of Inheritance. Ch. 3

Chromosomal Basis of Inheritance. Ch. 3 Chromosomal Basis of Inheritance Ch. 3 THE CHROMOSOME THEORY OF INHERITANCE AND SEX CHROMOSOMES! The chromosome theory of inheritance describes how the transmission of chromosomes account for the Mendelian

More information

Independent Assortment of Genes

Independent Assortment of Genes 3 Independent Assortment of Genes WORKING WITH THE FIGURES 1. Using Table 3-1, answer the following questions: a. If χ 2 is calculated to be 17 with 9 df, what is the approximate probability value? b.

More information

Worksheet for Morgan/Carter Laboratory #7 Mitosis and Meiosis

Worksheet for Morgan/Carter Laboratory #7 Mitosis and Meiosis Worksheet for Morgan/Carter Laboratory #7 Mitosis and Meiosis Ex. 7-1: MODELING THE CELL CYCLE AND MITOSIS IN AN ANIMAL CELL Lab Study A: Interphase How many pairs of homologous chromosomes are present

More information

Biology 1406 - Notes for exam 5 - Population genetics Ch 13, 14, 15

Biology 1406 - Notes for exam 5 - Population genetics Ch 13, 14, 15 Biology 1406 - Notes for exam 5 - Population genetics Ch 13, 14, 15 Species - group of individuals that are capable of interbreeding and producing fertile offspring; genetically similar 13.7, 14.2 Population

More information

The Genetics of Drosophila melanogaster

The Genetics of Drosophila melanogaster The Genetics of Drosophila melanogaster Thomas Hunt Morgan, a geneticist who worked in the early part of the twentieth century, pioneered the use of the common fruit fly as a model organism for genetic

More information

General Biology 1004 Chapter 8 Lecture Handout, Summer 2005 Dr. Frisby

General Biology 1004 Chapter 8 Lecture Handout, Summer 2005 Dr. Frisby Slide 1 CHAPTER 8 The Cellular Basis of Reproduction and Inheritance PowerPoint Lecture Slides for Essential Biology, Second Edition & Essential Biology with Physiology Presentation prepared by Chris C.

More information

Biology Behind the Crime Scene Week 4: Lab #4 Genetics Exercise (Meiosis) and RFLP Analysis of DNA

Biology Behind the Crime Scene Week 4: Lab #4 Genetics Exercise (Meiosis) and RFLP Analysis of DNA Page 1 of 5 Biology Behind the Crime Scene Week 4: Lab #4 Genetics Exercise (Meiosis) and RFLP Analysis of DNA Genetics Exercise: Understanding how meiosis affects genetic inheritance and DNA patterns

More information

Mendelian and Non-Mendelian Heredity Grade Ten

Mendelian and Non-Mendelian Heredity Grade Ten Ohio Standards Connection: Life Sciences Benchmark C Explain the genetic mechanisms and molecular basis of inheritance. Indicator 6 Explain that a unit of hereditary information is called a gene, and genes

More information

C1. A gene pool is all of the genes present in a particular population. Each type of gene within a gene pool may exist in one or more alleles.

C1. A gene pool is all of the genes present in a particular population. Each type of gene within a gene pool may exist in one or more alleles. C1. A gene pool is all of the genes present in a particular population. Each type of gene within a gene pool may exist in one or more alleles. The prevalence of an allele within the gene pool is described

More information

Science 10-Biology Activity 14 Worksheet on Sexual Reproduction

Science 10-Biology Activity 14 Worksheet on Sexual Reproduction Science 10-Biology Activity 14 Worksheet on Sexual Reproduction 10 Name Due Date Show Me NOTE: This worksheet is based on material from pages 367-372 in Science Probe. 1. Sexual reproduction requires parents,

More information

Lecture 7 Mitosis & Meiosis

Lecture 7 Mitosis & Meiosis Lecture 7 Mitosis & Meiosis Cell Division Essential for body growth and tissue repair Interphase G 1 phase Primary cell growth phase S phase DNA replication G 2 phase Microtubule synthesis Mitosis Nuclear

More information

Basic Principles of Forensic Molecular Biology and Genetics. Population Genetics

Basic Principles of Forensic Molecular Biology and Genetics. Population Genetics Basic Principles of Forensic Molecular Biology and Genetics Population Genetics Significance of a Match What is the significance of: a fiber match? a hair match? a glass match? a DNA match? Meaning of

More information

Part 1: Mitosis & Cytokinesis

Part 1: Mitosis & Cytokinesis Lab 5 - Bio 160 Name: Part 1: Mitosis & Cytokinesis OBJECTIVES Το observe the stages of mitosis in prepared slides of whitefish blastula and onion root tips. Το gain a better understanding of the process

More information

Chapter 8: Variation in Chromosome Structure and Number

Chapter 8: Variation in Chromosome Structure and Number Chapter 8: Variation in Chromosome Structure and Number Student Learning Objectives Upon completion of this chapter you should be able to: 1. Know the principles and terminology associated with variations

More information

BIO 184 Page 1 Spring 2013 NAME VERSION 1 EXAM 3: KEY. Instructions: PRINT your Name and Exam version Number on your Scantron

BIO 184 Page 1 Spring 2013 NAME VERSION 1 EXAM 3: KEY. Instructions: PRINT your Name and Exam version Number on your Scantron BIO 184 Page 1 Spring 2013 EXAM 3: KEY Instructions: PRINT your Name and Exam version Number on your Scantron Example: PAULA SMITH, EXAM 2 VERSION 1 Write your name CLEARLY at the top of every page of

More information

4.2 Meiosis. Meiosis is a reduction division. Assessment statements. The process of meiosis

4.2 Meiosis. Meiosis is a reduction division. Assessment statements. The process of meiosis 4.2 Meiosis Assessment statements State that meiosis is a reduction division of a diploid nucleus to form haploid nuclei. Define homologous chromosomes. Outline the process of meiosis, including pairing

More information

Genetics Module B, Anchor 3

Genetics Module B, Anchor 3 Genetics Module B, Anchor 3 Key Concepts: - An individual s characteristics are determines by factors that are passed from one parental generation to the next. - During gamete formation, the alleles for

More information

Key Questions. How is evolution defined in genetic terms?

Key Questions. How is evolution defined in genetic terms? Getting Started Objectives 17.1.1 Define evolution in genetic terms. 17.1.2 Identify the main sources of genetic variation in a population. 17.1.3 State what determines the number of phenotypes for a trait.

More information

B2 5 Inheritrance Genetic Crosses

B2 5 Inheritrance Genetic Crosses B2 5 Inheritrance Genetic Crosses 65 minutes 65 marks Page of 55 Q. A woman gives birth to triplets. Two of the triplets are boys and the third is a girl. The triplets developed from two egg cells released

More information

Heredity and Prenatal Development: Chapter 3

Heredity and Prenatal Development: Chapter 3 Genetics 1 DEP 4053 Christine L. Ruva, Ph.D. Heredity and Prenatal Development: Chapter 3 PRINCIPLES OF HEREDITARY TRANSMISSION Genotype Phenotype Chromosomes: in the nucleus of the cell store and transmit

More information

LAB : THE CHI-SQUARE TEST. Probability, Random Chance, and Genetics

LAB : THE CHI-SQUARE TEST. Probability, Random Chance, and Genetics Period Date LAB : THE CHI-SQUARE TEST Probability, Random Chance, and Genetics Why do we study random chance and probability at the beginning of a unit on genetics? Genetics is the study of inheritance,

More information

Activity: Pipe-cleaner Chromosomes

Activity: Pipe-cleaner Chromosomes Lecture Concept Chromosome structure, mitosis and meiosis Activity Type Group work with handout and physical models Time Needed in Discussion 50 minutes Activity: Pipe-cleaner Chromosomes Purpose To allow

More information

growth and tissue repair in multicellular organisms (mitosis)

growth and tissue repair in multicellular organisms (mitosis) Cell division: mitosis and meiosis I. Cell division -- introduction - roles for cell division: reproduction -- unicellular organisms (mitosis) growth and tissue repair in multicellular organisms (mitosis)

More information

Gene Mapping Techniques

Gene Mapping Techniques Gene Mapping Techniques OBJECTIVES By the end of this session the student should be able to: Define genetic linkage and recombinant frequency State how genetic distance may be estimated State how restriction

More information

Meiosis Poker. Other Resources A video demonstration of this lab is available free of charge on itunes and YouTube. Required Material:

Meiosis Poker. Other Resources A video demonstration of this lab is available free of charge on itunes and YouTube. Required Material: Meiosis Poker Objective Meiosis Poker is a simple lab designed to reinforce a student s understanding of meiosis. This lab can be performed in one class period (30+ minutes) and only requires a deck of

More information

Two copies of each autosomal gene affect phenotype.

Two copies of each autosomal gene affect phenotype. SECTION 7.1 CHROMOSOMES AND PHENOTYPE Study Guide KEY CONCEPT The chromosomes on which genes are located can affect the expression of traits. VOCABULARY carrier sex-linked gene X chromosome inactivation

More information