Pigment in mouse fur is only produced when the C allele is present. Individuals
ID: 194596 • Letter: P
Question
Pigment in mouse fur is only produced when the C allele is present. Individuals of the co genotype are white, If color is present, it may be determined by the A, a alleles. AA or Aa results in agouti color, while aa results in black coats. What FI and F2 genotypic and phenotypic ratios are obtained from a cross between AACC and aace mice? b. In three testcrosses between agouti females, whose genotypes were unknown, and males of the ace genotype, the following phenotypic ratios were obtained. What are the genotypes of these female parents? 9 agouti : 10 black 4 agouti: 5 black: 10 whiteExplanation / Answer
a) F0 AACC X aacc
AC X ac
F1 AaCc (all offsprings are agouties) (there is only one type of genotype and one type of phenotype in F1)
F2
AC
Ac
aC
ac
AC
AACC agouti
AACc
Agouti
AaCC Agouti
AaCc agouti
Ac
AACc
Agouti
AAcc
White
AaCc
Agouti
Aacc
White
aC
AaCC
agouti
AaCc
Agotui
aaCC
black
aaCc
black
ac
aACc
agouti
Aacc
White
aaCc
black
aacc
white
Phenotypic ratio= 9 agouti: 4 white:3 black
Genotypic ratio(9 different genotypes) =AACC : AACc: AaCC: AAcc: AaCc: Aacc: aaCC: aaCc: aacc =1:2:2:1:4:2:1:2:1
b.i) since the offsprings include agouti and the father is homozygous aa, in order to get agouti mother should contribute dominant A and since offsprings also include blacks mother has to contribute recessive 'a' too. so her genotype for A allele will be Aa. since there are no white offsprings there can be only dominant C allele in the mother. so mother's genotype is AaCC
b.ii) since offsprings include agouti and black mother would have contributed A, a and a dominant C, alleles. Since offsprings include white too, mother needs to contribute one recessive c allele .so her genotype is AaCc
AC
Ac
aC
ac
AC
AACC agouti
AACc
Agouti
AaCC Agouti
AaCc agouti
Ac
AACc
Agouti
AAcc
White
AaCc
Agouti
Aacc
White
aC
AaCC
agouti
AaCc
Agotui
aaCC
black
aaCc
black
ac
aACc
agouti
Aacc
White
aaCc
black
aacc
white