The answer to this question is the growth of the corpus
callosum. The Corpus callosum is the thick nerve that separates the two
hemisphere of the brain which is the left and right hemisphere of the brain. Corpus
Callosum is the part which allows the transmission of messages of the brain.
If you keep in mind that a child gets one gene from the father, andanother from the mother, all should be fine.
a) starting with the father: since he is infected, he then has atleast one P. Knowing his mother wasn't, then her genotype was pp.Since he must have gotten one of her genes, then the father'sgenotype is Pp.
Since her mother had normal eyes, she must have had pp, because ifshe had even one P, she would have ptosis -since the allele isdominant-.
Since the woman is infected, and her mother is pp, then for thesame reasoning as her father, her genotype is Pp.
b) so this is a cross between Pp X pp. Draw your punnets square.There's a 50% chance that her children will have pp genotype thusno ptosis. 50% of her children will have ptosis with genotype Pp.
