Question

In cats, curled ears result from an allele (Cu) that is dominant over an allele (cu) for normal ears. Black color results from an independently assorting allele (G) that is dominant over an allele for gray (g). A gray cat homozygous for curled ears is mated with a homozygous black cat with normal ears. All the F1 cats are black and have curled ears.

a. If two of the F1 cats mate, what phenotypes and proportions are expected in the F2?

b. An F1 cat mates with a stray cat that is gray and possesses normal ears. What phenotypes and proportions of progeny are expected from this cross?

Answer 1

TO KNOW THE PHENOTYPES AND THEIR PROPORTION WE FIRST FIND GENOTYPE OF PARENTS THEN WE FIND GAMETES PRODUCED BY THEM. THEN WE DRAW PUNNET SQUARE AND PUT ALL GAMETES IN BOXES OF PUNNET SQUARE ACCORDING TO THEIR PLACE.

Page 1 In cats. curled ears that is for normal result from an dominant over ears . allele (Cu) an allele (64) so, Phenotype Genotype Cu Cu ( Homozygous dominand) Curled ears Cu Cu (Heterozygous) Curted ears cucu ( Homozygous recessive) Normal egy Black color results from an independently assorting allele cal that is dominant over an allele for gray (8) Phenotype 50, Genotype GG (Homozygous dominant) Black Black ag (Heterozygous) 88 ( Homozygous recessive) Gray

Page - 2 A ears gray cat (Cucu) (99) homozygous is mated with for curled a cat coal with normal homozygous black ears (cucu). 00 gg Cu Cu x GG cucu meios's 1 meiosis Gamele Gamer gay Gay Gamere Fertilizaton Tag Cucu - F cats Black Curled and have cars, - two of the fi eats mare, (a) If then - GgCucu 1 x Cg Cucu let one cat is male other is and female ..

Page 3 male x female male Gg Cucu GgCucu meiosis meiosis male .gamere female gamere Peennett male temate ga gamere Square - - a Cu Gau I geu gou . Glu Ga Cuca Black and curled ears Black Curled and ears - Ger - GG Cucu Black and curted ears GG Cucu Black and curled ears GG cucu Black and normal ears GgCucu Black and cured ears agucu Black and normal ears Gg Cucu glu Block and Curied egrs Gg Cucu you Black and curled ears Ag Cucu Black and cured cars Agaucu Black and normal ears 88 Сасу Gray and curled ear Яагисц Gray and normal ears Gglucu Black and curted ears gg Cucu I Gray and curled ears . gg aucu I Gray and curled ears z cats.

Page 4 Phenotypes (0) Black brodu ced and curled ane - ears Proportion of black and curled ears = q = 0.5625 (2) Black and normal ears Proportion of black and normal ears = 3 = 0.1875 (3) Gray and curled ears Proportion of gray and curted ears = L = 0.1875 O. 1875 - (4) Gray and normal ears Proportion of gray and normal ears = to = 0.0625 Canswer)

1. (b) An Stray Ecat (Ag Cucu) cat that is mates gray Pages with a and possesses normal ears. So, Genotype of stray cat is ggcucu let, cat is male and other one female . Male Female F cat stray cat Gg Cucu Igcucu meios's meiosis (goul female gamete male gameres only one type of gamete produce from this genotype

Page 6 mavel Pennent square temperpere Gcu 7 Gen Gg Cucu , agucu | Black and Black and L gou Ugument I gcu . gg Cucu I Gray and ggcucu Gray and curled ears normal ears Curled cars nomal eart produced from the cross. ag Cucu Phenotypes and . ggauch are - (1) Black and curled ears . Proportion and Curted ears of = Black 5 = 0.25 (2) Black and normal oart. Proportion of black and normal en normal ears = = 0.25

(3) Gray and curled ears Page 7 Proportion curled ears of = gray = and 0: 25 + (4) Gray and normal ears Proportion of normal cars gray and = 0.25 = Canswer).