In: Biology
18. Short hair in rabbits is governed by a dominant gene (L) and long hair by a recessive allele (l). Black hair results form the action of the dominant genotype (B_) and brown from the recessive genotype (bb). In a cross between homozygous short, black haired rabbit and a homozygous long, brown haired rabbit what are the phenotypic and genotypic ratios of the F1 and F2 generation.
Genotype of homozygous short and black haired rabbit - LLBB.
Genotype of homozygous long, brown haired rabbit - llbb.
Cross LLBB X llbb
Gametes formed LB lb
F1 generation LlBb(short and black haired rabbit) X LlBb
Gametes formed LB, Lb, lB and lb LB, Lb, lB and lb.
F2 generation:
Male/Female | LB | Lb | lB | lb |
LB | LLBB(short and black haired rabbit) | LLBb(short and black haired rabbit) | LlBB(short and black haired rabbit) | LlBb(short and black haired rabbit) |
Lb | LLBb(short and black haired rabbit) | LLbb(short and brown haired rabbit) | LlBb(short and black haired rabbit) | Llbb(short and brown haired rabbit) |
lB | LlBB(short and black haired rabbit) | LlBb(short and black haired rabbit) | llBB(long and black haired rabbit) | llBb(long and black haired rabbit) |
lb | LlBb(short and black haired rabbit) | Llbb(short and brown haired rabbit) | llBb(long and black haired rabbit) | llbb(long and brown haired rabbit) |
The phenotypic ratios of the F1 generation- All are short and black haired rabbit.
The genotypic ratios of the F1 generation - All have LlBb genotype.
The phenotypic ratios of F2 generation - 9:3:3:1.
Short and black haired rabbit - 9
Short and brown haired rabbit - 3.
Long and black haired rabbit - 3.
Long and brown haired rabbit - 1
The genotypic ratios of F2 generation - 1:2:2:4:1:2:1:2:1.
LLBB - 1.
LLBb - 2.
LlBB - 2.
LlBb - 4.
LLbb - 1.
Llbb - 2.
llBB - 1.
llBb - 2.
llbb - 1.