if brian has a son who is color-blind, what is known about the genotype of the son's mother?; which are different forms of the same gene? genotypes phenotypes alleles traits; in the pedigree that is shown, which represents irene's allele combination? xhxh xhxh xhxh xhy; which combination of alleles are always involved in the inheritance of a sex-linked trait?; which family members have red-green color blindness?; based on the pedigree that is shown, which describes john; which is not considered a sex-linked trait?; what is the purpose of using a pedigree?