Mapping a Cave Fish Genome: Polygenic Systems and Regressive Evolution

• DOI: 10.1093/jhered/93.1.19
• Publication Date: 2002-07-26T18:57:29Z
• Authors: R. Borowsky
• Keywords: Genome Scan

We used random amplified polymorphic DNA (RAPD) fingerprinting to generate anonymous markers in the fish Astyanax mexicanus, a species with both surface and cave populations. Surface individuals are eyed pigmented; troglobitic forms blind depigmented. hybridized Pachon population produced RAPD genomic map 1064 cM length (about half total of genome) that was screen for quantitative trait loci (QTL) troglomorphic traits. Three QTL reduced eye size, two decreased numbers melanophores, condition factor, locus unifactorial trait, albinism, were mapped. These factors account an average 46% variance these traits backcross. The results first direct demonstration changes this multifactorial. Two closely linked pairs found. Each consisted regressive constructive QTL. close linkages unlikely have occurred by chance (P < .05 each) suggest evolution might be facilitated pleiotropy or genetic hitchhiking.