Question

Some cats (commonly referred to as "tuxedo cats") exhibit white spotting patterns on their fur. This white spotting trait is controlled by a single gene (S). Three phenotypes are possible for cats based on their genotype at the S locus.

SS results in high grades of white spotting (white) cats.

Ss results in medium grades of white spotting (tuxedo) cats.

ss results in solid colored cats with no spotting.

You are studying an isolated population of cats where a certain disease results in a 50% mortality rate of solid colored cats before breeding age. This population consists of 150 white cats and 200 tuxedo cats.

What is the allele frequency of the capital S allele in your population of cats?

a.

0.1225

b.

0.8775

c.

0.7143

d.

0.2857

e.

None of the above

Your initial population of cats is left to breed randomly between themselves. After one generation of breeding, you count 1000 progeny. How many solid colored cats would you expect to find? (Note: throughout your problem solving, you should round to four decimal places until you reach your final answer, when you will round to a whole number)

a.

43

b.

41

c.

39

d.

82

e.

None of the above

The tuxedo phenotype is highly sought after. Two breeders want to produce as many tuxedo cats as they can, so they have a competition with each other. Breeder 1 takes 250 white cats and 250 tuxedo cats to an island. Breeder 2 takes 200 white cats and 300 tuxedo cats to a different island. After one generation of random mating within the two separate populations, which breeder will have produced more tuxedo cats?

a.

Breeder 1

b.

Breeder 2

c.

They will have produced the same number of tuxedo cats

Answer 1

1. Frequency of S allele = c. 0.7143

2. Expected solid colored cats = b. 41

3. Answer = b. Breeder 2

1. 150 white cats Tuxedo cats - 200 2x ss + Ss Frequency of S allele 2x Total individuals 2x 150 + 200 2x350 - 500 700 0.7143 2. our initial allele Frequency of S = 0.7143 1- S so, S - 10.7143 0.2857 0.7143 X 0.7143 = 0.5102 Expected genotype Frequency # white cat (ss) Tuxedo cat (255) = 2*0.7143 X 0.2857 = 0.4082 solid colored cat (ss) = 0.2857 x 0.2857 = 0.8816 So, Expected number of solid colored cat 81.62 0.0816 x 1000

50% mortality rate of solid colored eats half of the solid colored cats will die so 81.62 so, solid colored cats = = 40.81 41 2 3. Breeder 1 » 250 Sss 250 ss= 2x5st Ss OP Frequency s allele 2x tofal poperlations 1500 + 250 1000 750 1000 - 0.75 0.25 1 -0.75 : of s s allele Frequency of Expected Frequency of Tuxedo cat (ss) 2 X 0.75 X 0.25 37.5 % 0.375

Breeder 2 → Ss= 300 200 ss= s allele 2X200 + 300 1000 Frequency 700 1000 0.7 I-0.7 = 0.3 Frequency of s allele = Tuxedo cats (55) Expected frequency of 0.42 or 42 % 2x0.7 0.3 - So, Breeder a produce more Tuxedo cats Breeder la 37.5% Tuxedo cats Breeder 2= 42% Tuxedo cats