Biology Chapter 7 Beyond Mendel Notes

Transcription

1 Biology Chapter 7 Beyond Mendel Notes Phenotype: Genotype: What is Mendelian inheritance controlled by? Incomplete Dominance:. Example of Incomplete Dominance:

2 Example Number 2 When green betta fish (B 1 B 1 ) are crossed with a steel blue betta fish (B 2 B 2 ) all the offspring have the heterozygous genotype (B 1 B 2 ). These offspring will be royal blue in color. Practice Problem: What is the phenotypic ratio with two royal blue betta fish are crossed? Practice Problems: The petal color of four o clocks (flowering plants) is inherited by incomplete dominance. Plants with R 1 R 1 genes have red flowers. Plants with R 2 R 2 genes have white flowers. Plants with R 1 R 2 genes have pink flowers. 1. Joey planted snapdragons in his garden. All the seeds came from one set of parent plants. When the flowers bloomed, Joey saw that all of his flowers were pink. What are the genotypes of the parent plants? Include a punnett square in your answer. Genotype of the parents: and

3 2. Kory also planted snapdragons in his garden. All of his seeds came from one set of parents. When his plants bloomed, 50% were white and 50% were pink. What are the genotypes of the parent plants? Include a punnett square in your answer. Genotype of the parents: and 3. Casie, Zach, and Kelly each have beautiful gardens of snapdragon flowers. Casie has a garden of red snapdragons and would like to create a new section to her garden including only pink four snapdragons. Zach breeds only pink snapdragons and Kelly breeds white snapdragons. From whose garden will Casie have the greatest probability of creating a pink population of snapdragons flowers? Create two punnett squares to prove your point. Casie s Flowers x Zach s Flowers Casie s Flowers x Kelly s Flowers From whose garden will Casie choose mates for her flowers?

4 Codominance:. Example of Codominance: Practice Problems: The gene for the coat color of shorthorn cattle in inherited by codominance. Red Shorthorn cattle have RR genes. White shorthorn cattle have WW genes. Roan (coat of both red and white hairs) cattle have RW genes. 1. Determine the genes of the offspring if a red cow and a roan bull are bred. Show a punnett square. What % of offspring should have red coats? white coats? roan coats? % red coats: % white coats: % roan coats: 2. Determine the offspring of two roan parents. Show a punnett square. What percentage of offspring should have red coats? white coats? roan coats? % red coat: % white coat: % roan coat:

5 3. In chickens, the allele for black feathers (B) is co-dominant with the allele for white feathers (W). Heterozygous chickens appear speckled with black and white feathers. A black chicken breeds with a heterozygous speckled chicken. What are the genotypic and phenotypic ratios? Show a punnett square. Genotypic Ratio: Phenotypic Ratio: 4. A rooster and chicken mate. When the chicks hatch 3 are speckled, 2 are black and 1 is white. What are the parents s genotypes? Draw a punnett square to show your work. Parent s Genotypes: and

6 Practice: Codominance and Incomplete Dominance Name: Mods: Directions: Look at the following examples. State whether each of the following is an example of Co-dominance or Incomplete dominance. Then create genotypes based off of the given phenotypes. Remember that the medium trait must always be heterozygous. An example has been done for you. Example: Black, grey, or white. This is incomplete dominance because neither trait is being fully expressed, it s a blend. Genotypes: B 1 B 1 Black B 2 B 2 Grey B 2 B 2 White a. Birds can be blue, white, or white with blue-tipped feathers. b. Flowers can be white, pink, or red. c. A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked. d. A Sneech can be tall, medium, or short. e. A dog can be spotted, black, or white. f. I ate a chocolate chip cookie, an Oreo cookie, and a chocolate chip Oreo cookie for lunch. g. There were three types of flowers: green, blue, and yellow. h. I raise cows, obviously, I have a black angus and a shorthorn cow. I cross these two cows and get a ½ angus, ½ shorthorn.

7 1. In smileys, eye shape can be starred, circular, or a circle with a star. Write the genotypes for the pictured phenotypes. 2. Is this an example of incomplete dominance or a co-dominance inheritance pattern? 3. Show the cross between a star-eyed and a circle-eyed. 4. What are the phenotypes of the offspring? 5. What are the genotypes? 6. Show the cross between a circle-star eyed, and a circle eyed. 7. What percent of the offspring have circle-eyes? 8. What percent of the offspring have circle-star eyes?

8 9. Show the cross between two circle-star eyed. 10. What percent of the offspring are circle-eyed? 11. What percent of the offspring will have circle-star eyes? 12. What is the possibility or chance of having a star-eyed child? 13. Complete the punnet square for a cross between a homozygous red-flowered snapdragon (R 1 R 1 ) and a homozygous white-flowered snapdragon (R 2 R 2 ). Give the genotype(s) and phenotype(s) of the offspring in the F1 generation. Genotype(s): Phenotype(s): 14. When traits are inherited in an incomplete dominance pattern, what is true of the phenotype of the heterozygotes? 15. Complete the punnett square for a cross between two pink-flowered F1 plants. Give the phenotype ratio of the offspring in the F2 generation. Phenotype ratio:

9 16. In what type of inheritance are both alleles expressed equally? 17. Complete the Punnett square for a cross between a black chicken (BB) and a white chicken (WW). Give the phenotype of the offspring in the F1 generation. Key BB - Black WW white BW - checkered Phenotype of offspring: 18. What type of inheritance pattern is this?

10 Multiple Alleles: Example(s) of Multiple Alleles: Note: Even though there are multiple alleles for certain traits an individual can only carry alleles because. Blood Types are also an example of multiple alleles. How many different types of blood are there? What are the four blood types? How many alleles control the blood types? Blood Types A and B are. Blood Type O is. Why is it important for you to know your blood type? The blood type that is known as the Universal acceptor is. Universal acceptor means that people with this blood type can receive blood from anyone, It doesn t matter what their blood type is. The blood type that is known as the Universal donor is. Universal donor means that their blood can be given to any individual regardless of their blood type.

11 Practice Problems: Your blood type is controlled by multiple alleles. Blood type is controlled by three alleles in which A (I A ) and B (I B ) are codominant, and both are dominant over O (ii). Type A Blood = I A I A or I A i Type B Blood = I B I B or I B i Type O Blood = ii Type AB Blood = I A I B 1. If your mom has type AB blood and your dad has type O blood then what blood types could your siblings have? Draw a punnett square to show the cross and possible offspring. What are the possible blood types (phenotypes) of your siblings? What are the possible genotypes from these two parents? 2. A man with blood type B marries a woman with blood type A. They have four children, one with the blood type AB, one with blood type A, one with the blood type B and one with the blood type O. Draw a punnett square showing the cross. What are the genotypes of each parent? Genotypes of Parents: and

12 The chart below lists the blood phenotypes of 8 individuals. Use the information in the chart to solve the genetics problems that follow. Females Blood Type Males Blood Type Anne Type O Charlie Type A Wendy Type B Scott Type AB Susan Type AB Larry Type O Patricia Type A Keith Type B 3. Larry has a son with type B blood. Which of the females listed above could be this child s biological mother? Biological mother could be: 4. Keith and Wendy have a 4 year old son with type O blood. How is this possible? Use a punnett square as part of your answer.

13 Blood Type compatibility: What is an antibody? How do they relate to blood types? Can differences between a mother and fetus s blood cause risks to the baby or mom? Explain: Polygenetic Inheritance: Example(s) of Polygenetic Inheritance: Most human traits are. Eye Color -There are known genes that control human eye color. -Green alleles are to blue alleles -Green alleles are to brown alleles This does not account for all eye colors, like,, or eye color that changes overtime or patterns in eye color. Scientist hypothesize that we have not all the that control eye color.

14 Epistasis In mice, different genes affect. Two genes give the mouse a. One affects the. One determines if it will have The fifth determines if it will have. - gene that can interfere with the expression of other genes. - a lack of pigment in skin, hair and eyes. A mouse that is for the alleles that prevent of the skin will be white regardless of what those other genes code for. Environmental Influences Effects of genes can be altered by the. The genetic make-up of an organism at fertilization determines In what two ways can the environment affect the genetic make-up of an organism? Examples of each:

15 Boy vs. Girl All somatic, or regular chromosomes are identical pairs Do sex chromosomes always match? Why or why not? Does the sperm or egg determine the sex of a baby? Why? X-Chromosome Inactivation Since males have one and one, they express all of the on both chromosomes. Even if males have all genes, they will still be. In females ( ) one of the is turned off, this is. Because one X-chromosome is randomly turned off, females are a of two types of cells. One type with an active X-chromosome from and one with an active X-chromosome from. Examples: Female calico cats have white fur and alleles for black and orange fur that are expressed randomly in some cells. Since males have only 1 X chromosome they can have black or orange.

16 Sex-Linked Traits:. What is the fate of a male who inherits an x-linked trait? Why? Will a female who inherits an x-linked trait have the same fate? Why or why not? Example of Sex-Linked Traits: Carrier: Can sex-linked traits be hidden? Explain:

17 Practice Problems: The human blood clotting disorder is a recessive trait (must receive both recessive alleles to express trait) which is found on the X chromosome. X H X H and X H X h = females without hemophilia X h X h = female with hemophilia X H Y = male without hemophilia X h Y = male with hemophilia 1. A woman who is heterozygous for hemophilia mates with a male without hemophilia. What percent of the female offspring will be a carrier for hemophilia (heterozygous)? Describe the phenotypes of the boy offspring. Percent of female offspring that are carriers: Male offspring s phenotypes: 2. A woman who is a carrier mates with a male with hemophilia. Will any girls have hemophilia?

18 Below is a chart listing some alien sex-linked characteristics. Use the chart to solve the genetics problems below. Trait Chromosome Dominant Phenotype Recessive Phenotype Body Color X Purple (P) Pink (p) Eye Color X Yellow (E) Red (e) Extra Arms Y Extra arms present (4) Extra arms present (4) 3. A male with yellow eyes mates with a red-eyed female. What is the chance that this couple will have a baby boy with red eyes? Probability of baby boy having red eyes: % 4. A female, heterozygous for the body color trait mates with a pink male. What is the chance that these aliens will give birth to a purple-skinned girls? Purple-skinned Girl: % Genetic Disorder: Mutation:

19 What is the difference between a treatment and a cure? Cystic Fibrous What is it? What are the symptoms? What is the treatment Dominant or Recessive or Sex-linked Other Important Information: Sickle Cell Anemia What is it? What are the symptoms? What is the treatment Dominant or Recessive or Sex-linked Other Important Information:

20 Hemophilia What is it? What are the symptoms? What is the treatment Dominant or Recessive or Sex-linked Other Important Information: Huntington s What is it? What are the symptoms? What is the treatment Dominant or Recessive or Sex-linked Other Important Information:

21 Down Syndrome What is it? What are the symptoms? What is the treatment Dominant or Recessive or Sex-linked Other Important Information: Diagnosing Genetic Disorders What two things did Doctors rely on in the past in order to determine genetic disorders? and What two things do Doctors rely on today in order to determine genetic disorders? and How does the process of amniocentesis lead to a karyotype? Karyotype: Karyotypes are arranged in pairs by and of centromeres.

22 Genetic Counseling What does a genetic counselor do? Who might visit a Genetic counselor? Pedigree: It is an important tool that geneticists use to A pedigree is a chart or that

23 Common Symbols Used In Pedigrees Male Female Marriage (Husband and Wife) Parents to their children Siblings (Brothers and Sisters) Individual is affected by trait (shows up) Carrier of the trait Death Successive Generations are labeled by Individuals are labeled by