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Question

Chinchilla coat color in mice is due to a recessive allele (c^ch) and the normally pigmented coat, called "agouti," is due to the dominate allele. Mice heterozygous for chinchilla coat color are mated to homozygous chinchilla (c^ch/ c^ch) mice, and the resulting progeny include both agouti and chinchilla phenotypes. if one takes one of the agouti progeny and it mates it into one of its chinchilla sibs, the expected genotypic ratio among their offspring is - (A) 3: 1, (B) 1:1, (C) 9:3:3:1, (D) 1:2:1, (E) none of these.

Answer 1

Solution:

1. The agouti progeny is a heterozygote because one of its parents was a homozygous chinchilla. Let's call that genotype(A^ch/c^ch).

2.. The heterozygous agouti from (1) is crossed with a chinchilla sib (c^ch/c^ch): (A^ch/c^ch) x (c^ch/c^ch)

3. As simply as possible, there is a 50/50 probability that the agouti parent will bestow its agouti allele on any one offspring while the chinchilla parent can only bestow a chinchilla allele; over a large poluation of offspring from such a cross, the results should therefore converge towards a 1:1 ratio of agouti heterozygotes vs. homozygous chinchillas.

Answer 2

Parents = Ch/ch (agouti) x ch/ch (chinchilla)
Progeny = 50% Ch/ch , 50% ch/ch

Test cross = Ch/ch x ch/ch
Testcross Progeny= 50% Ch/ch , 50% ch/ch = 1:1

Answer 3

The blood varieties are A, B, AB and O. those come from the genotypes AA or AO, BB or BO, AB and OO, so A and B have 2 achieveable genotypes. you'll be able to desire to look at what blood type the young ones might desire to artwork out the genotype of each and each make sure- each and each make sure passes on 0.5 their genotype to each and each infant. undergo in recommendations O is recessive, and somewhat shows up by using actuality the blood team if the guy has no A or B gene. this potential that a= AO ( by using actuality the O make sure might desire to be OO, and a has to grant one infant an A and one an O), b=BO ( in basic terms like the 1st answer) c=AB ( back, the comparable stable judgment) d=BO, pondering the reality that she or he might desire to get an O from the O blood team make sure, which hides at the back of the dominant B allele e=AO, comparable ingredient f=BO, pondering the reality that AO crossing with BO is the only thank you to get all 4 blood communities as siblings. desire you already be attentive to this, all of this is clever as rapidly as you spot the suited judgment.