Practice question

Sex-influenced traits derive from autosomal genes present equally in males and females, but hormonal environment determines dominance relationship. Androgens versus estrogens alter transcription thresholds, enhancer activity, or receptor sensitivity, making same genotype dominant in one sex and recessive in other. Reciprocal crosses for such loci still produce identical genotypic ratios because autosomal transmission independent of sex, unlike sex-linked traits located on X or Y. Phenotypic discordance arises physiologically, not by chromosome segregation difference, reflecting hormone modulation of gene expression rather than sex chromosome linkage.