Skip to main content
Dryad logo

Heterozygosity–fitness correlations reveal inbreeding depression in neonatal body size in a critically endangered rock iguana

Citation

Moss, Jeanette B.; Gerber, Glenn P.; Welch, Mark E. (2020), Heterozygosity–fitness correlations reveal inbreeding depression in neonatal body size in a critically endangered rock iguana, Dryad, Dataset, https://doi.org/10.5061/dryad.8kprr4xj1

Abstract

Inbreeding depression, though challenging to identify in nature, may play an important role in regulating the dynamics of small and isolated populations. Conversely, greater expression of genetic load can enhance opportunities for natural selection. Conditional expression concentrates these opportunities for selection and may lead to failure of detection. This study investigates the possibility for age-dependent expression of inbreeding depression in a critically endangered population of rock iguanas, Cyclura nubila caymanensis. We employ heterozygote-fitness correlations to examine the contributions of individual genetic factors to body size, a fitness-related trait. Nonsignificant reductions in homozygosity (up to 7%) were detected between neonates and individuals surviving past their first year, which may reflect natural absorption of inbreeding effects by this small, fecund population. The majority of variation in neonate body size was attributed to maternal or environmental effects (i.e., clutch identity and incubation length); however, heterozygosity across 22 microsatellite loci also contributed significantly and positively to model predictions. Conversely, effects of heterozygosity on fitness were not detectable when adults were examined, suggesting that inbreeding depression in body size may be age dependent in this taxon. Overall, these findings emphasize the importance of taking holistic, cross-generational approaches to genetic monitoring of endangered populations.

Funding

Mohamed bin Zayed Species Conservation Fund, Award: 142510107

Rufford Foundation, Award: 20068-2

Rufford Foundation, Award: 17568-1

Rufford Foundation, Award: 23086-B

International Iguana Foundation