You have four pure-breeding strains of mice that all have white fur. Crosses between brown females from a wild-type strain and white males from your four strains produce only brown progeny, indicating that all four strains carry a recessive mutation that causes white fur. You cross all of the white strains to each other as indicated in the table below, and record the fur color of the offspring.
Mother strain Father strain Progeny
Cross #1 A B brown
Cross #2 A C brown
Cross #3 A D white
Cross #4 C B white
Cross #5 D B brown
Cross #6 D C brown
Cross #7 B A brown females, white males
Cross #8 C A brown females, white males
Cross #9 D A white
Cross #10 B C white
Cross #11 B D brown females, white males
Cross #12 C D brown females, white males
Complete the following table of progeny genotypes from the crosses listed above. You will need as many loci (columns) as there are number of different genes carrying white-fur mutations (this may be more or fewer than three loci). In each row indicate the genotype of the progeny of that cross at all loci. Denote white-fur alleles with w and brown-fur alleles with +. If there are loci where the genotype differs between males and females, list both genotypes and indicate which genotype belongs to each sex.
Cross # locus1 locus2 locus3 ....
1 + +
2
3
4
5
6
7
8
9
10
11
12
In a few sentences, describe why some crosses produce all brown offspring, some crosses produce all white offspring, and some produce brown and white offspring. Use the following terms in your answer: complement, fail to complement, X-linked, autosomal.
You have four pure-breeding strains of mice that all have white fur. Crosses between brown females from a wild-type strain and white males from your four strains produce only brown progeny, indicating that all four strains carry a recessive mutation that causes white fur. You cross all of the white strains to each other as indicated in the table below, and record the fur color of the offspring.
Mother strain Father strain Progeny
Cross #1 A B brown
Cross #2 A C brown
Cross #3 A D white
Cross #4 C B white
Cross #5 D B brown
Cross #6 D C brown
Cross #7 B A brown females, white males
Cross #8 C A brown females, white males
Cross #9 D A white
Cross #10 B C white
Cross #11 B D brown females, white males
Cross #12 C D brown females, white males
Complete the following table of progeny genotypes from the crosses listed above. You will need as many loci (columns) as there are number of different genes carrying white-fur mutations (this may be more or fewer than three loci). In each row indicate the genotype of the progeny of that cross at all loci. Denote white-fur alleles with w and brown-fur alleles with +. If there are loci where the genotype differs between males and females, list both genotypes and indicate which genotype belongs to each sex.
Cross # locus1 locus2 locus3 ....
1 + +
2
3
4
5
6
7
8
9
10
11
12
In a few sentences, describe why some crosses produce all brown offspring, some crosses produce all white offspring, and some produce brown and white offspring. Use the following terms in your answer: complement, fail to complement, X-linked, autosomal.
