Inquiry 4

Cats have two sex chromosomes. Chromosomes carry genes and genes have traits like coat
color, eye color etc. Sex chromosomes define gender. Females produce only X chromosomes in their egg and males produce both X and Y chromosomes in their sperm. Unlike other coat color genes, the gene that determines red coloration can be carried only on the X chromosome. The gene that determines red or orange coloration in cats is called O (for orange). (O = orange, o = non-orange). If the cat inherits an O pattern proper for its gender the cat will be red or orange.  This orange will cover up all other colors. If the cat inherits an o pattern it won’t be orange.

Males only have one X chromosome so they either have an O gene or not. Females get one X
from each parent, so they get two O genes. In regular Mendelian Genetics the O and o genes
would behave like dominant and recessive genes. However in cats because these genes are
located on the X chromosome some cells in each female will be expressing the O gene which just happens to be on the active X and in other cells the o gene will be on the active X. Complete the following Punnet Square and Probability Problems and determine the outcome of breeding the following cats.
1. Calico female and non-orange male. (5 points)
 
 

What are the genotypes of the offspring? ______________________________________
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What are the phenotypes of the offspring? _____________________________________
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What are the phenotypes of the offspring?_____________________________________
______________________________________________________________________
What are the genotypes of the offspring? _____________________________________
______________________________________________________________________
3. Orange female and non-orange male (5 points)
 
 
 

What are the phenotypes of the offspring? ______________________________________
________________________________________________________________________
What are the genotypes of the offspring? _______________________________________
________________________________________________________________________