In humans, short fingers and widows peak are dominant over long fingers and continuous hairline. A heterozygote reproduces with a heterozygote .what is the chance of any one child’s having the same phenotype as the parents?
1 Answer
Chances of any child having the same phenotype are almost 50%.
Explanation:
The calculated phenotypic ratio of the offsprings as result of cross between two heterozygous parents both having short fingers and widows peak is explained below:
A cross occurs between two parents with genotype Ss Ll (SsLl X SsLl) is considered as per question.
Each parent will produce 4 types of gametes: SL, Sl, sL and sl.
The possible permutation and combination by chance fusion of 4 types of gametes produced by each parent can be calculated by checkerboard.
The phenotypic ratio between phenotypes: short fingers widows peak, short fingers continuous hairline, long fingers widows peak and long fingers and continuous hairline will be 9:3:3:1.
The chances of the offsprings having the same phenotype as the parents (Short fingers and widows peak) will be 9 out of 16 (56.25%).
Thus the chances of any offspring having same phenotype as the parents will be approx. 50%.
