A black mouse mates with a brown mouse, and all the offsprings are black.
(a) Why are no brown offsprings produced ?
(b) If two of the black offsprings mate with each other what kind of offspring would you expect and in what proportions ? Give reason for your answer.
A black mouse mates with a brown mouse, and all the offsprings are black.
(a) Why are no brown offsprings produced ?
(b) If two of the black offsprings mate with each other what kind of offspring would you expect and in what proportions ? Give reason for your answer.
(a) When the black mouse mates with the brown mouse to give all black offspring it means that the black allele of skin colour is dominant over the brown allele of skin colour. In heterozygous conditions, the black allele will express itself thus giving a black coloured phenotype to the mouse. The skin colour is a trait that has two alleles - dominant black allele and recessive brown allele and its selective expression will determine the skin colour of the mouse.
(b) 3 black and 1 brown because it is a monohybrid cross and for a monohybrid cross, the phenotypic ratio will be 3: 1
(a) When the black mouse mates with the brown mouse to give all black offspring it means that the black allele of skin colour is dominant over the brown allele of skin colour. In heterozygous conditions, the black allele will express itself thus giving a black coloured phenotype to the mouse. The skin colour is a trait that has two alleles - dominant black allele and recessive brown allele and its selective expression will determine the skin colour of the mouse.
(b) 3 black and 1 brown because it is a monohybrid cross and for a monohybrid cross, the phenotypic ratio will be 3: 1
