Exam 1 - The Fundamental Principles of Genetics: Single-gene Inheritance

allele

• alternative DNA sequences at the same gene locus

• different _____ can produce different amounts or forms of a gene product

identical sister chromatids

DNA replication produces two _____ with homologous chromosomes that replicate so each daughter cell receives the same genetic information

phenylketonuria

PKU

phenylalanine hydroxylase

PAH

reduced PAH function

PKU variants = _____

haplosufficient

observed in mutations in genes that are functionally _____ (mutated allele is recessive allele)

haploinsufficient

in genes that are _____ (mutated allele is dominant allele)

X, X

females have XX and males have XY and _____ determines phenotype if carried on _____ chromosome

square

what pedigree symbol signifies a male?

circle

what pedigree symbol signifies a female?

solid symbol

what pedigree symbol signifies an afflicted individual?

a line through symbol

what pedigree symbol signifies a death due to the disease?

X-linked recessive disorders

• more affected males

• carrier mothers can have affected sons

• no father to son transmission

X-linked dominant disorder

• affected father = all daughters affected, no sons affected

• affected heterozygous mother = 50% of daughters and 50% of sons

autosomal recessive

affected child can have unaffected parents; both sexes; may skip generations

autosomal dominant

usually appears in successive generations; both sexes

X-linked recessive

more affected males; no father-to-son transmission

X-linked dominant

affected father → all daughters, no sons

Y-linked

affected father → all sons only