Practice question

Recessive alleles can remain hidden in heterozygous carriers who show normal phenotype, allowing trait to remain undetected for one or more generations until two carriers happen to mate and produce homozygous recessive child. Pedigree then shows unaffected parents producing affected child, creating apparent skipping of generations. Traits appearing in every generation without skip suggest dominant inheritance with vertical transmission, while male-only vertical patterns suggest Y-linkage, and father-to-son transmission reliably excludes X-linkage. Therefore generation skipping combined with equal sex ratio strongly points to autosomal recessive mode.