The A and B antigens in humans may be found in
water-soluble
form in secretions, including saliva, of some individuals
(Se/Se
and Se/se) but not in others (se/se). The population thus
con-
tains “secretors” and “nonsecretors.”
(a) Determine the proportion of various phenotypes (blood
type and ability to secrete) in matings between individuals
that
are blood type AB and type O, both of whom are Se/se.
(b) How will the results of such matings change if both
parents
are heterozygous for the gene controlling the synthesis of the
H
substance (Hh)?