Lesson C3 2 Exploing Genetics Unit C. Basic Pinciples of Agicultual/Hoticultual Science Poblem Aea 3. Undestanding Cells, Genetics, and Repoduction Lesson 2. Exploing Genetics New Mexico Content Standad: Pathway Stand: Animal Systems Standad: IV: Know the factos that influence an animal s epoductive cycle to explain species esponse. Benchmak: IV-B: Discuss epoductive cycles to show how they diffe fom species to species. Pefomance Standad: 2. Discuss the implications of genetic vaiation. Student Leaning Objectives. Instuction in this lesson should esult in students achieving the following objectives: 1. Descibe how the gende of offsping is detemined. 2. Explain how genotype and phenotype ae diffeent. 3. Distinguish between qualitative and quantitative inheitance Unit C. Poblem Aea 3. Lesson 2. Page 1.
List of Resouces. The following esouces may be useful in teaching this lesson: Recommended Resouces. One of the following esouces should be selected to accompany the lesson: Bake, MeeCee and Robet E. Mikesell. Animal Science Biology & Technology. Danville, Illinois: Intestate Publishes, Inc., 1996. (Textbook, Chapte 2) Othe Resouces. The following esouces will be useful to students and teaches: Ensminge, M.E. Animal Science. Danville, Illinois: Intestate Publishes, Inc., 1991 (Textbook, Chapte 3) Lee, Jaspe S., et al. Intoduction to Livestock and Companion Animals, Second Edition. Danville, Illinois: Intestate Publishes, Inc., 2000. (Textbook, Chapte 8) Lee, Jaspe S. and Diana L. Tune. AgiScience, Thid Edition. Danville, Illinois: Intestate Publishes, Inc., 2003. (Textbook, Chapte 5) Made, Sylvia S., Biology. Dubuques, Iowa: Wm. C. Bown Publishes, 1993. (Textbook, Chapte 5) List of Equipment, Tools, Supplies, and Facilities Witing suface Ovehead pojecto Tanspaencies fom attached mastes Copies of student lab sheets Tems. The following tems ae pesented in this lesson (shown in bold italics): Alleles Codominance Dominant Gametes Genes Genotype Gego Mendel Heteozygous Homozygous Incomplete dominance Phenotype Qualitative taits Quantitative taits Recessive Unit C. Poblem Aea 3. Lesson 2. Page 2.
Sex chomosomes Zygote Inteest Appoach. Use an inteest appoach that will pepae the students fo the lesson. Teaches often develop appoaches fo thei unique class and student situations. A possible appoach is included hee. Have students count the numbe of students who have bown eyes, blue eyes, and geen eyes. Then ask the eye colo of each student s paents. Discuss the elationship between paents eye colo and students eye colo. Summay of Content and Teaching Stategies Objective 1: Descibe how the gende of offsping is detemined. Anticipated Poblem: What detemines the gende of offsping? I. The study of genetics is concened with the tansfe of taits. Gego Mendel discoveed that these taits ae inheited though units called genes. Mendel futhe discoveed that genes wee found in pais and half of the inheited taits come fom the fathe and half fom the mothe. A. Gametes o sex cells, known as the spem fom the male and egg fom the female, meet in fetilization and mix genetic mateial fom both. The esulting zygote contains genes fom both mothe and fathe, and displays chaacteistics fom both. B. Detemination of the sex of zygote depends on the sex chomosomes. Male sex chomosomes ae eithe X o Y. A zygote that eceives a Y chomosome fom spem will be male. A zygote that eceives an X chomosome fom spem will be female. The male makes sex detemination as all eggs fom female eceive an X chomosome. Theefoe, a female zygote will have two X chomosomes (XX) while a male zygote will have one X and one Y chomosome (XY). Use TM: C3 2A to discuss with students how sex of the esulting zygote is detemined. Chapte 6 in Animal Science Biology and Technology is ecommended to assist you students in masteing this infomation. Objective 2: Explain how genotype and phenotype ae diffeent. Anticipated Poblem: How ae genotype and phenotype diffeent? II. Resulting offsping of epoduction have both genotype and phenotype heedity. A. Genotype is the actual genetic code. It contols physical and pefomance taits. The genotype of an oganism cannot be changed by envionmental factos. Unit C. Poblem Aea 3. Lesson 2. Page 3.
B. Phenotype is the oganism s physical o outwad appeaance. This is the pat of the genotype the oganism expesses o shows. In some instances, phenotype may be alteed by the oganism s envionment. C. A homozygous oganism is one having simila alleles o genes on the DNA molecule fo a paticula tait. While a heteozygous oganism is one having diffeent alleles fo a paticula tait. A vaiety of techniques can be used to help students maste this objective. Students need text mateial to help undestand the diffeence between genotype and phenotype. Chapte 6 in Animal Science Biology and Technology is ecommended to assist you students in masteing this infomation. Objective 3: Distinguish between qualitative and quantitative inheitance. Anticipated Poblem: What is the diffeence between qualitative and quantitative taits? III. The genes contained in an oganism contol taits of that oganism. Some taits ae contolled by only one pai of genes, while othes equie seveal pais. A. Qualitative taits ae taits contolled only by a single pai of genes and cannot be alteed by the envionment. Thei phenotype is eithe one thing o the othe. These taits most easily show how genes ae inheited. An example is coat colo. B. Quantitative taits ae taits contolled by seveal pais of genes. These taits ae expessed acoss a ange. These taits can also be alteed by envionment. Examples include ate of gain, gowth ate, backfat depth, etc. C. Not all taits contained within an oganism ae expessed. Dominant taits cove up o mask the alleles fo ecessive taits. In some oganisms thee ae cases of codominance of taits in which both dominant and ecessive genes ae expessed. Incomplete dominance may also occu. This happens when a blending of the allele pai is expessed. Seveal diffeent methods and techniques may be used to aid students in leaning this mateial. Students need text mateials to help undestand how taits ae tansfeed and expessed in oganisms. Chapte 6 in Animal Science Biology and Technology is a ecommended efeence. Also use TM: C3 2B and C3 2C to discuss this mateial with you students. Also incopoate LS: C3 2A to show students the Punnett Squae method. Review/Summay. Use the student leaning objectives to summaize the lesson. Have students explain the content associated with each objective. Student esponses can be used in detemining which objectives need to be eviewed o taught fom a diffeent angle. Questions at end of chaptes in the textbook may also be used in the eview/summay. Application. Application can involve the following student activity using the attached lab sheet: LS: C3 2A: PUNNETT SQUARE Unit C. Poblem Aea 3. Lesson 2. Page 4.
Answes to Sample Test: Pat One: Matching 1=c,2=a,3=d,4=g,5=f,6=b,7=i,8=c,9=h Pat Two: Completion 10. Gego Mendel 11. sex chomosomes 12. phenotype 13. Dominant, ecessive 14. genetics Pat Thee: Shot Answe Pp Pp Pp Pp 15. Pp 16. 0:4:0 (homozygous dominant: heteozygous: homozygous ecessive) 17. 4:0 (dominant: ecessive) Unit C. Poblem Aea 3. Lesson 2. Page 5.
Sample Test Name Test Lesson C3 2: Exploing Genetics Pat One: Matching Instuctions. Match the tem with the coect esponse. Wite the lette of the tem by the definition. a. alleles d. genotype g. phenotype b. codominance e. genetics h. heteozygous c. homozygous f. qualitative taits i. incomplete dominance 1. Study of heedity. 2. Two genes that contain infomation fo the same tait. 3. The genetic code of the oganism. 4. The expessed pat of the genetic code. 5. Taits which ae contolled by a single pai of genes. 6. Tait in which both genes in the pai ae expessed. 7. Tait in which a blending of the genes is expessed. 8. Allele made of two identical genes. 9. Allele made of one of both possible genes fo a cetain tait. Pat Two: Completion Instuctions. Povide the wod o wods to complete the following statements. 10. discoveed that taits ae inheited though units called genes. 11. Detemination of the sex of zygote depends on the. 12. is the oganism s physical o outwad appeaance. 13. taits cove up o mask the alleles fo taits. 14. The study of is concened with the tansfe of taits. Unit C. Poblem Aea 3. Lesson 2. Page 6.
Pat Thee: Shot Answe Instuctions. Povide infomation to answe the following questions. Use the Punnett Squae method to estimate the possible gene combinations fo the following situation. Mating a polled cow (PP) to a honed bull (pp). 15. What would be the offsping s gene combination? 16. What would the genotype atio be? 17. What would the phenotype atio be? Unit C. Poblem Aea 3. Lesson 2. Page 7.
TM: C3 2A Chomosome Combinations Detemine Sex Female Gem Cell II Key: I = Female Chomosome = Male Chomosome I Male Gem Cell I I I Egg I I I I Spem 1 2 3 4 II FEMALE I MALE NOTE: If spem 1 o 2 unites with the egg, the pogeny will be a female, but if spem 3 o 4 unites with the egg, the pogeny will be a male. Unit C. Poblem Aea 3. Lesson 2. Page 8.
TM: C3 2B Red Sie (RR) R R White Dam () R Roan R Roan R Roan R Roan Roan Sie (R) R White Dam () R Roan White R Roan White Unit C. Poblem Aea 3. Lesson 2. Page 9.
TM: C3 2C Sie (BB) B B Red Dam (bb) b Bb Bb b Bb Bb Sie (Bb) B b Dam (Bb) b Bb bb Red B BB Bb Unit C. Poblem Aea 3. Lesson 2. Page 10.
LS: C3 2A Name Lab Sheet Punnett Squae Instuctions: Use the Punnett Squae method to estimate the possible gene combinations. Wite the equied infomation in the squaes. 1. Mating a female, which is heteozygous fo hons (Pp) to a honed bull (pp). a. What would be the genotype atio? b. What would be the phenotype atio? 2. Mating a con plant that is heteozygous fo geen leaf colo (Gg) with a con plant that is homozygous fo the ecessive white leaf colo (gg). a. What would be the genotype atio? b. What would be the phenotype atio? 3. Mating a plant caying a heteozygous gene fo height (Tt) with anothe heteozygous plant. (T = tall, t = shot) Unit C. Poblem Aea 3. Lesson 2. Page 11.
c. What would be the genotype atio? d. What would be the phenotype atio? 4. Mate a polled, black cow (PpBb) with a polled, black bull (PpBb) P = polled; p = honed; B = black; b = ed. a. How many phenotypes ae possible? b. List each phenotype and the numbe of offsping with that phenotype. Unit C. Poblem Aea 3. Lesson 2. Page 12.