Question

(Q21-25) We have the following three sets of mouse breeding experiments. The table summarizes the number of each category of the F2 progeny. These breeding results were obtained in a similar fashion as shown in the lecture, starting from two pure-bred homozygous lines as the Parental stage, which were followed by the heterozygous F1. The subsequent F1 was testcrossed with the breeding partners with homozygous recessive alleles. Wild-type alleles are indicated with +, and the mutant alleles without + are all recessive.

​Exp I,​​​Exp II, ​​​Exp III

​No (genotype)​ No (genotype)​No (genotype)

Cat1​50 (a ,b ,c )​​400 (e ,f ,g )​​50 (h ,i ,k )

Cat2​50 (a+,b+,c+)​​400 (e+,f+,g+)​50 (h+,i+,k+)

Cat3​50 (a ,b ,c +)​​40 (e ,f ,g+ )​​50 (h ,i ,k+)

Cat4​50 (a+,b+,c )​​40 (e+,f+,g )​​50 (h+,i+,k )

Cat5​50 (a ,b+,c+)​​40 (e ,f+,g+)​​100 (h ,i+,k+)

Cat6​50 (a+,b ,c )​​40 (e+,f ,g )​​100 (h+,i ,k )

Cat7​50 (a ,b+,c )​​20 (e ,f+,g )​​100 (h ,i+,k )

Cat8​50 (a+,b ,c+)​​20 (e+,f ,g+)​​100 (h+,i ,k+)

21. Which breeding represents the independent assortment of all three genes?

A. Exp I

B. Exp II

C. Exp III

D. all of the above

E. none of the above

22. Which breeding represents the genetic linkage of all three genes through one chromosome and what is the gene order?

A. Exp I​a-b-c

B. Exp I​a-c-b

C. Exp II​e-f-g

D. Exp II​f-e-g

E. Exp III​h-i-k

23. In Exp II, which categories represent the two parental types?

A. Cat 1 and 2

B. Cat 3, and 4

C. Cat 5 and 6

D. Cat 7 and 8

E. all of them

24. Which breeding represents the genetic linkage of two out of three genes and also which is a pair of two linked genes?

A. Exp I​b-c

B. Exp I​a-c

C. Exp III​h-i

D. Exp III​h-k

E. Exp III​i-k

25. Which is the correct mapping distance in Exp III?

A. 33% between h and I

B. 33% between h and k

C. 33% between i and k

D. none of them linked.

E. all of them linked.

Answer 1

expll distance between h I gene 400 Ton =.67 Loof 100 +100 +100 600 2 distance 300 50 600 I,K - is 100+ 100+50+50 600 I kn liked

22 - Ans order of exp I gene- distomee between a and b gene Recombinent total 500+ 6501 750+ 850 4000 7 more distance 2800 - 400 b and c 3500 35oot usof 750 +850 yooo 6 less distance = 2400 - 4ooo clasaly linked the order of gene b, c are in a exp I is b ca is exp II distance between enf no tuot 20 +20 gene 120 1000 - 1000 F , g gene 160 not uod tuo tuo 1000 order of gene is е F 9