hbio pedigrees & punnet squares

autosomal dominant

• does not skip a generation

• unaffected parents always have unaffected children

• affected children have at least 1 affected parent

autosomal recessive

• can skip a generation

• unaffected parents have an affected child

• 1 affected parent can have an unaffected child

sex-linked

• skips a generation

• mostly males affected

• affected fathers do not pass to their sons

complete dominance

when the dominant allele completely masks the effect of the recessive allele in heterozygous conditions

incomplete dominance

when both alleles of a gene are partially expressed, creating a blend in heterozygous conditions

co-dominance

when both alleles of a gene are equally expressed in heterozygous conditions

genotype

 the two alleles a person has inherited for a particular gene

phenotype

the detectable physical expression of a genotype

homozygous

genotypes made of the same alleles

heterozygous

genotypes made of two different alleles