The influence of parental relatedness on reproductive success

Abstract

The relationship between ¢tness and parental similarity has been dominated by studies of how inbreeding depression lowers fecundity in incestuous matings. A widespread implicit assumption is that adult ¢tness (reproduction) of individuals born to parents who are not unusually closely related is more or less equal. Examination of three long-lived vertebrates, the long-¢nned pilot whale, the grey seal and the wandering albatross reveals signi¢cant negative relationships between parental similarity and genetic estimates of reproductive success. This e¡ect could, in principle, be driven by a small number of low quality, inbred individuals. However, when the data are partitioned into individuals with above average and below average parental similarity, we ¢nd no evidence that the slopes di¡er, suggesting that the e¡ect is more or less similar across the full range of parental similarity values. Our results thus uncover a selective pressure that favours not only inbreeding avoidance, but also the selection of maximally dissimilar mates.

Age‐dependent, negative heterozygosity–fitness correlations and local effects in an endangered Caribbean reptile, Iguana delicatissima

“…MLH was estimated according to three different approaches: standardized heterozygosity (SH; Coltman, Pilkington, Smith, & Pemberton, 1999), internal relatedness (IR; Amos et al., 2001), and heterozygosity by locus (HL; Aparicio, Ortego, & Cordero, 2006). Both IR and HL are inversely related to SH in that a positive correlation between heterozygosity and fitness is indicated by a negative correlation between IR or HL and the fitness trait (Aparicio et al., 2006).…”

Inbreeding, heterozygosity and fitness in a reintroduced population of endangered African wild dogs (Lycaon pictus)

“…Standardized multilocus heterozygosity (stMLH) was calculated based on the proportion of loci genotyped for a given individual that was heterozygous divided by mean heterozygosity in the population at the same loci (Coltman et al 1999;Slate et al 2004). IR reflects the relatedness of the parents of an individual by determining the degree of allele-sharing relative to random expectations across all loci (Amos et al 2001). Standardized mean d 2 (hereafter referred to as d 2 ) is a measure focused on events deeper in the pedigree than individual heterozygosity (Hedrick et al 2001) and is based on the genetic distance between parental gamete genomes (Coulson et al 1998(Coulson et al , 1999.…”

“…Therefore, departure from SMM was tested for all loci with the program BOTTLENECK (Cornuet and Luikart 1996). The stMLH, IR and d 2 values were calculated using an EXCEL macro written by Amos et al (2001).…”

“…Molecular metric assessments have led to HFC discoveries involving fitness traits such as fecundity (Amos et al 2001), immunocompetence (Coltman et al 1999), recruitment (Jensen et al 2007) and survival (DaSilva et al 2006). Although small populations of endangered species are most vulnerable to inbreeding and fitness reduction (Fitzpatrick and Evans 2009), most HFC studies have focused on large populations of common species (see Grueber et al 2008 for review).…”

“…Molecular metrics are commonly used as a surrogate for pedigree inbreeding coefficients (f), because the latter can be logistically difficult to obtain within natural populations. The most frequently used molecular metrics of heterozygosity in HFCs analyses include standardized multilocus heterozygosity (stMLH; Coltman et al 1999), internal relatedness (IR; Amos et al 2001) and standardized mean d 2 (Coulson et al 1998). However, it has been suggested that the correlation between molecular heterozygosity and pedigree inbreeding coefficients is too weak to be of biological significance (Coltman and Slate 2003;Balloux et al 2004;Slate et al 2004;Hansson and Westerberg 2008).…”