Pedigree Rules and Inheritance Patterns

Vocabulary flashcards covering the recognition rules and inheritance patterns for autosomal recessive, autosomal dominant, X-linked, Y-linked, and mitochondrial traits in pedigrees.

Autosomal recessive traits

Traits in pedigrees characterized by affected individuals born to unaffected parents, equal occurrence in males and females, absence in some generations, and $100\%$ affected children if both parents are affected.

Rare autosomal recessive alleles

Abnormal alleles for rare conditions where most individuals do not carry the allele, and those who do carry it in the heterozygous form.

Autosomal dominant traits

Traits in pedigrees where affected individuals have an affected parent, both sexes are affected equally and can transmit the allele, two unaffected parents never have affected children, and two affected parents can have an unaffected offspring.

Lethal dominant mutant alleles

A condition where carrying two dominant (mutant) alleles can be fatal, causing dominant traits to often present in the heterozygous state.

X-linked recessive traits

Traits in pedigrees where more males are affected than females, no male carriers exist, affected males produce $100\%$ carrier daughters and no affected sons, and unaffected males produce no affected female offspring.

X-linked dominant traits

Traits where an affected female passes the trait to $50\%$ of offspring, and an affected male passes the condition to $100\%$ of daughters but never to sons.

Y-linked traits

Traits where $100\%$ of affected individuals are male, and an affected father passes the condition to all sons, differentiating it from X-linked recessive inheritance.

Mitochondrial inheritance pattern

An inheritance pattern where all offspring of an affected mother are affected, but NONE of the offspring of an affected father are affected.