K.C.S.E Biology Q & A - MODEL 2018PP1QN18
A tall, light skinned lady with pimples on her face has long hair and limps.
(a) List two features which the lady has that are due to inheritance.
(b) Explain why most recessive genes are expressed phenotypically in male offspring of humans.
(a) Height (tallness);
Skin colour (light);
(b) Most of the genes are sex-linked and are carried on the X - chromosomes; boys receive X chromosomes from the mother (and Y chromosomes from the father); if the X carries a recessive gene, it is more likely to be phenotypically expressed in boys;