Why Study Cats?

1. Cat Genetics http://www.pictures-of-cats.org/#4 & http://en.wikipedia.org/wiki/Cat_coat_genetics

2. Why Study Cats? • Large population within our community • Cats mate randomly • Easy to find • Breeding not controlled by people • Avoid “pure breeds” like Siamese • Conditions mimic a wild population

3. Why Cats? Cont. • Cats coats are controlled by many genes (polygenic) and many types of inheritance • Dominant / recessive • Incomplete dominance w/variable expression • Multiple alleles • Epistasis • X-linked & X-inactivation and more!

4. Dominant White • WW or Ww is white not albino. ww has color. W_ is epistatic to all other genes

5. Short hair is dominant • LL or Ll is short hair. This cat is ll

6. Agouti is dominant • All tabby cats have the Agouti gene: A_ if each hair is a solid color, the cat is aa.

7. If this cat is male he is XOY If this cat is female, she is XOXO Males that are non orange are Xo Y Females that are not orange are Xo Xo Orange is X-linked dominant

8. ww L_ aa o What is this cat?

9. First she must be female (or extremely rare Klinefelters XXY) X inactivation has caused her patchy colors XoXO allows her to have both orange and other colors What is a Calico Cat?

10. If orange is diluted to cream or light yellow, they are dd All others are D_ Dilute color is recessive

11. Dilute color is recessive • If black is diluted to blue-gray, • All others are D_

12. A_ D_ A_ cats seem to have two colors of fur. This is because the Agouti gene causes the black pigment to be deposited in bands in some of the hair. In the darker stripes (or swirls or blotches) the black bands compeletely cover each hair, while in the lighter regions, there are bands of black with bands of a lighter color, thus that region of the fur appears to be a lighter color. It is caused by each hair in that region being two-toned. If the dark pigment, and hence the dark stripes, is black, the cat is NOT dilute. A_ D_ oo A_ dd oo ?? D_ OO A_ dd oo ?? dd OO A_ dd Cats who are A_ still make the bands of color in some of the hairs, while some of the hairs are solid color, again giving the appearance of stripes. However, the color is diluted to gray so they are dilute. In Orange cats, you can’t score the Agouti locus – there will be stripes no matter if it is A_ or aa. But dilute still will lighten the orange color in the dark stripes to more of a yellow. aa D_ Cats who are aa can NOT make the bands of color in the hairs, and every hair is therefore a solid color. If that color is black, the cat is NOT dilute. aa dd Cats who are aa dd can NOT make the bands of color in the hairs, and every hair is therefore a solid color. But that color is gray (or smoky or bluish) so the cat is dilute.

13. This is an example of variable expression of incomplete dominance ss has no white fur Ss has less than 50% white SS has more than 50% white Piebald spotting

14. Piebald spotting • This is an example of variable expression of incomplete dominance • SS has more than 50% white

15. This is an example of variable expression of incomplete dominance Ss has less than 50% white Piebald spotting

16. Polydactyl condition is dominant in humans too! P_ Commonly called “mitten” foot in cats Non polydactyl is pp Polydactylism is dominant

17. Polydactyl condition is dominant in humans too! P_ Why don’t we see more people with this condition? Cats practice random mating! Polydactylism is dominant

18. Polydactyl condition in humans