| Popis: |
Decreased genome-wide heterozygosity of inbred individuals can result in reduced survival and reproductive fitness (i.e. inbreeding depression). However, showing such heterozygosity–fitness correlations in endangered species, especially those that are already genetically impoverished, has proven to be difficult. New Zealand's kakapo (Strigops habroptilus) is a critically endangered, flightless parrot that now survives only on islands free of introduced predators. The recent population bottleneck of 51 individuals, lek mating system (where only females care for eggs and young) and the fact that all but one of the population's founders came from the same insular population, render them particularly susceptible to inbreeding depression. The present study uses 25 microsatellite loci to derive estimates of relatedness to investigate heterozygosity–fitness correlations in kakapo. After accounting for the effects of co-variables, there was no evidence that male heterozygosity affected variation in egg fertility, but there was evidence that female heterozygosity affected fecundity (i.e. clutch size) and hatching success; that is, more homozygous females lay smaller clutches and had lower hatching success. The present study detected significant heterozygosity–fitness correlations and demonstrates that inbreeding is a contributing factor towards relatively low hatching success, which in turn reduces population growth in this highly endangered, flightless parrot. |
Plný text