explain the relationship between homozygous and heterozygous genotypes and the resulting phenotypes in examples of co-dominance
(Please note that this is not “incomplete dominance” where each allele partly suppresses the expression of the other as in pink flowers of snapdragons. The HSC Biology syllasbus does not refer to incomplete dominance. Some web sites will have these two concepts confused. If in doubt, check in written references.)
Alleles present | Blood type |
---|---|
AA or AO | A |
BB or BO | B |
OO | O |
AB | AB |
R | R | |
---|---|---|
W | RW | RW |
W | RW | RW |
When the roan cattle are crossed:
R | W | |
---|---|---|
R | RR | RW |
W | RW | WW |
Half the offspring will be roan while a quarter will be red and quarter white.