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Homework Cat Alleles

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Homework Cat Alleles

Postby HelpPleaseThankYou » Wed Feb 29, 2012 8:51 am

Okay, so I spent three hours trying to figure this out. I used my notes, my text book and the internet and could not find any explanation that helped. I tried various combinations and a 25 box Punnett Square and could not get all of the solutions. I am beyond frustrated...mainly because the first question doesn't even seem grammatically correct (my professor is notorious for that) and because it was never properly explained. We did a VERY QUICK example in class that was similar but all we did was take the mother and father genotypes and come up with fractions for possibilities. There weren't any unknowns for the parents and when I went back and looked at the diagram, it didn't even make sense. My professor is very smart, a little too smart, lol. Sometimes the professor flies through the information which makes homework very difficult. I spent many hours in school today so, maybe I am just tired, but I feel like if I spend anymore time trying to figure this out that I will let my other homework and studying responsibilities slide. If someone can please help me figure this out, I would really appreciate it. This is only one section of a very large packet and I've completed everything else, this is just the one part that I'm having trouble understanding.

Here is the allele key that I was given:

COAT COLORATION AND PATTERNING GENES IN CATS LOCUS GENOTYPES

W or Ww all white
B or Bb black
C or Cc full color
D or Dd intense color
A or Aa agouti (tabby)
cscs Siamese (Coat color with points Mask on face, legs, tail)
dd dilute color (with Bb = blue (gray) with bb = lilac)
aa non-agouti (solid color)
bb brown or chocolate
ww non-white


Challenge 1: Mate a chocolate, (Dd), Siamese, tabby (AA) female with a lilac, solid color, male homozygous for all trait. What are the possible genotypes and phenotypes of the progeny and what proportions are expected?

I did not understand the question and it seems grammatically off to me. Is the professor asking to mate a chocolate "bb," intense color "Dd," Siamese "cscs," tabby (AA) mother with a a lilac "bb dd," solid color "aa" male? Why is she pointing out that the male is homozygous? It's obvious that all of those traits are homozygous recessive, or is she just being redundant? I'm not sure if there is something that I am missing? Also, is the genotype for lilac really "bb dd?" Because that is very confusing to me... Once I get the genotype figured out for the male, do I just make a Punnett Square or a diagram?

Challenge 2: A female lilac of genotype "ww bb CC dd aa" produced a litter of four kittens:
1 black kitten, 1 blue kitten, 1 brown tabby, 1 lilac tabby
a. What were the genotype and the phenotype of the father?
b. Could these parents produce a lilac (same phenotype as the mother?) Show your work.


For a. I thought that the phenotype was black and brown tabby and the genotype that I got was "ww Bb AA dd bb," because I figured there needed to be a "Bb" for the black kitten, an "AA" for the tabby kittens and a "dd" was needed because in order for the lilac and blue kittens to be possible, both parents need to carry the recessive trait. But no matter what I did, I could not get the combinations to produce a lilac tabby kitten which leads me to believe that my genotype is wrong and no matter what I did, I could not figure it out. Again, I could be really tired, but I have so much other homework and quizzes to prepare for, I feel like I'm spending too much time on these problems. For b. I did say that the parents could produce a lilac kitten because both parents carry the trait for it and after using a Punnett Square and combining alleles from both parents, I was able to produce a lilac kitten, but that's dependent on whether or not the genotype that I found is even correct.

Can someone please help me figure this out? I would really appreciate it. This is very last minute because this was assigned to me today, but it is due on Thursday. So, if you could get back to me before then, I would appreciate it. If not, I can hand in what I have completed but would still like some opinions because I'm sure something similar to this will be on the upcoming exam. Thank you in advance.
HelpPleaseThankYou
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Re: Homework Cat Alleles

Postby HelpPleaseThankYou » Wed Feb 29, 2012 3:23 pm

After trying again this morning, I figured it out.

I would have deleted the thread, but there is no option to do so. Oh well, lol.
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