Mendelian Genetics Lecture 4 Vocab

Sex Chromosomes, Lethal Alleles, & More Gene Interactions

sex-linked gene

gene located on a sex chromosome (usually X)

pseudoautosomal region

genes present on both X and Y (e.g., Mic2)

hemizygous

having only one copy of an X-linked gene (males)

Y chromosome

shrinking, repetitive, little recombination; useful for tracing paternal lineage

X-linked recessive

e.g., Duchenne muscular dystrophy (DMD), Drosophila white-eye mutant

lethal allele

an allele that causes death, skewing expected phenotypic ratios (e.g., 2:1 instead of 3:1); example: dominant Manx cat allele (homozygous lethal)

complementation test (applied)

pairwise crosses to count how many genes underlie a set of mutant strains (e.g., zebrafish albino pigment mutants)