Crossing a black short haired (BBSS) guinea pig with a brown long haired (bbss) guinea pig results in an F1 breed of black short haired (BbSs) guinea pigs. Inbreeding F1 black shorthair (BbSs) guinea pigs resulted in F2 progeny with 9 black shorthair, 3 black longhair, 3 brown longhair and 1 brown longhair guinea pig.
here,
The gene responsible for black color is B
Genotype BB is black
And the gene S responsible for short fur
Short hair genotype SS
Consequently, the black color and short hair genotype is BBSS
again,
Gene responsible for brown color b
Brown color genotype bb
And the gene responsible for long hair s
The long haired genotype ss
Consequently, the brown color and long hair genotype is bbss
The first progeny is F1 and the second progeny is F2
Parents : ♂ × ♀
Phenotype : Black color – short hair Brown color – long hair
Genotype : BBSS bbss
Gamete : (BS) (bs)
F1 Generation : BbSs
Self fertilization : F1×F1
Parents : ♂ × ♀
Phenotype : Black color Short hair Black color Short hair
Genotype : BbSs BbSs
Gamit : (BS) (Bs) (bS) (bs) (BS) (Bs) (bS) (bs)
F2 Generation (checker board)
Remarks: From the checker board, out of 16 guinea pigs, 9 are black-short hair, 3 black-long hair, 3 brown-long hair and 1 brown-long hair guinea pig.
Phenotypic Ratio: Black-Short Hair: Black-Long Hair: Brown-Long Hair: Brown-Long Hair = 9:3:3:1