Question

Vanilla mice! Someone please help. I am having a hard time with this material and want to make sure that I am on the right track. "Fur color in mice is under the control of (at least) three unlinked loci...

Question 4: (4 points) Fur color in mice is under the control of at least) three unlinked loci. The C gene determines whether melanin is produced at all; the B gene influences the amount of melanin that is deposited in each strand of fur; and the A gene regulates the location where melanin is placed on the fur strand. At the C locus, the dominant allele C allows for melanin production, while the recessive allele c prevents it. The absence of melanin results in a condition termed albinism. At the B locus, the dominant allele B results in high melanin production and thus black strands, while the recessive allele b produces brown strands (due to decreased melanin production). At the A locus, the dominant allele A produces a zone of yellow just below the tip of each strand of hair giving a mottled appearance known as agouti. Expression of the recessive allele a causes the yellow zone to be absent, resulting in a solid-color coat. a. Match the following genotypes to their corresponding phenotypes: Genotypes: CCBBAA Ccbbaa CcbbAA ccBBAa CCBbaa Phenotypes: Albino; Black Agouti; Brown Agouti; Solid-brown; Solid-black b. A female with genotype CcBbAa and a male with genotype ccBLAA. What are the expected genotypes and phenotypes of their offspring? c. One of the albino mice from the F2 is successively crossed with the same black agouti mouse to produce several litters. These litters include all five mice phenotypes: albino, black agouti, solid-black, brown agouti, and solid-brown mice. What can be concluded about the genotypes of the albino and black agouti mice?

Answer 1

1 UT Aus.a):- Genotypes © CCBBM ® Cobbaa (3) СcЬБАА CCBBAA © CCBbaa ӨOево Рисионари Black, Agouti Brown, solid (solid-brown) Brown, agouti Aьир Solid- black - x CC3%AA ) Слосс : - Gameter : Сс ВЬAn А = СВА | -B-A = CBA a = Ева А - €ьАН No = Сьа 27А- - СВА очи - сва- A=cba b- A cbA ХЬ " - СБ4 - cba СВА, СВА, СЬA, Ca,CBA, сва, cbl, eba

СВА aba СВА сва СЬA cba СсВРАЛ Black, agouti) ССРВАЛ TC Black, colid 17 Сс ВЬАА (Васк, одрин), СсыАл T Black, agouti) II сс ВРАА: CAыио) СcBRA Т( Albио) севья Albino ССР.rЛА C Blour, agouti)] CC BbAa Black, Agouri Cabba [[Porouon, agouti) Ccbbla TC Brown, agouti] ссы САМЫійо)! CCB bla CAlbino СВА cba CEA СcЬБА ТСНЫіио) eba Ссы Аа (Hыио) ccbbla Ibup)1 Phenotypic ratio : - Albino : Brown-agouti : Black agouri : Black g : 2 :"s: 1 un ratio - CeBBA1: CCBLAA : CC Blaa .CcBbAa: Ccbbat : ecbbla! ccPBAA: ссыљАА: ceBBa:cbba'есьЬAA',с о |:2:1:2:1:1:1:1:2:1:2:1:1:1

Ans c) From the above case, it can be concluded that by interbreeding the albino mice  can be made to produce non- albino mice because the three genes are unlinked. For the genotypes, there is a range of different genotypes that can produce albino and black agouti litters. Different genotypes but same phenotype.