1. Animal Genetics: Animal Genetics: Dominant vs. Recessive Traits Intro to Agriculture Science

2. GOALS:  Explain the difference between dominant and recessive genes.  Use a Punnett Square to predict genotypic and phenotypic ratios of offspring.

3. What do we already know? review…

4. Phenotype  Appearance!  Result of Genotype Example: Bw = Black Coat Because B is dominant

5. Genotype  The genetic makeup!  Alleles from parents  What you can’t see Example: Alleles that code for good milk production.

6. Alleles  A pair of genes  That code for the same trait Example: Hair Color Eye Color Height

7. What do we need to know? vocabulary…

8. Dominant Genes  Determine what the offspring will look like!  Expressed as capital letters  Mask recessive genes. Example: B=Black w=White Dominant Allele = B

9. Recessive Genes  Sometimes determine what the offspring will look like.  Expressed as lowercase letters Example: B=Black w=White Recessive allele = w

10. What is it called when both alleles are the same?  Homozygous

11. Example AA or aa

12. Identify... Dominant & Recessive AA or aa ? ?

13. Homozygous Dominant Homozygous Recessive

14. What is it called when both alleles are different?  Heterozygous

15. Example Aa

16. Lets Get to It! Genetic Crosses Monohybrid Crosses Punnett Squares Genetic Crosses Punnett Squares Monohybrid Crosses

17. What the heck are they?  Punnett squares are genetic crosses used by biologists to predict the probability that certain traits will be inherited by offspring.

18. What do they look like?  Punnett Square:

19. MONOHYBRID CROSS  A Punnett Square  Using one pair of contrasting traits  Ex: hair color

20. Example #1:  Homozygous vs. Homozygous

21. Example #1:  A White Sow (ww) crossed with  A Black Boar (BB)

22. B B (BB) ww (ww) Bw Homozygous vs. Homozygous

23. Example #2:  Homozygous vs. Heterozygous

24. Example #2:  A White Sow (ww) crossed with  A Black Boar (Bw)

25. B w (Bw) ww (ww) Bw ww Homozygous vs. Heterozygous

26. Example #3:  Heterozygous vs. Heterozygous

27. B w (Bw) Bw BB Bw ww Heterozygous vs. Heterozygous

28. Result…

29. Try it! cfu…