- A population has only two alleles, R and r, for a particular gene. The allele frequency of R is 20%.What are the frequencies of RR, Rr, and rr in the population. Show all your work.
Ans:
p = frequency of dominant allele R = 0.20
q = frequency of recessive allele r = 0.80
p2 = frequency of homozygous dominant (RR) = (0.2)2 = 0.04
2pq = frequency of heterozygous (Rr) = 2(0.2)(0.8) = 0.32
q2 = frequency of homozygous recessive (rr) = (0.8)2 = 0.64
2. A large population consists of 400 individual, of which 289 are homozygous dominant (MM) , 102 are heterozygous (Mm) and 9 are homozygous recessive (mm). Determine the allele frequencies of M and m.
Ans:
Genotypes: MM Mm mm
no of individual: 289 102 9
(total 400)
Genotype frequency : 289/400 102/400 9/400
=0.7225 =0.255 =0.0225
No. of M alleles: 289x2 102 x1 9 x0
578 102 0 =680
No. of m alleles: 289x0 102x1 9x2
0 102 18 =120
Phenotypes:
"M" allele frequency = 680/800 = 0.8 5
"m" allele frequency = 120/800 = 0.15.
3. Genotype frequency of AA=56%, Aa=38%, aa= 6%
B) frequency of A= 1.5%. a=.55
4.
a) 0.3
b).042
c)0.3%
5. a)0.6
b)0.4
c)40%
d)48%
6. a).98%
b)0.02%
c) 0.04%
Suppose the feather color of a bird is controlled by two alleles, D and d. The D allele results in dark feathers, while the d allele results in lighter feathers.
1. Suppose two Dd birds mate. What percentages of DD, Dd, and dd offspring would you predict? Use the Punnett square at right to help determine your answer.
DD < 25%> Dd < 50%> dd <25% >
2. In this situation, what ratio of heterozygous (Dd) to homozygous (DD and dd) offspring would you expect to find? <1:1 >