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Introduction to Pedigrees

Author(s): Lisa M. Meffert, PhD

Marfan's Syndrome:Parental Genotypes Known

We now can focus on families where the parental genotypes are known. We know the remaining affected individuals must have received their "M" from their mothers, since their fathers were normal ("mm"" genotypes). Thus, their other allele must have come from their fathers. Since the fathers are homozygous for "m," each one of their offspring must have received an "m" allele.