Heterosis and Outbreeding Depression in Descendants of Natural Immigrants to an Inbred Population of Song Sparrows (Melospiza Melodia)

Marr, Amy B.; Keller, Lukas F.; Arcese, Peter

doi:10.1554/0014-3820(2002)056[0131:haodid]2.0.co;2

Cited by 72 publications

(104 citation statements)

References 80 publications

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“…Thus, heterozygote advantage in terms of parasite load may counteract the high parasitemia of immigrants, who are likely to produce the most heterozygous offspring. A parallel situation has been reported in an island population of song sparrows (Melospiza melodia) in which immigrants are less likely than residents to breed, but the outbred offspring of these immigrants have high survivorship (Marr et al 2002). Similarly, migration among subpopulations may (through maintaining genetic variability) enhance the ability of mountain white-crowned sparrows to cope with endoparasites and other pathogens.…”

Section: Discussionmentioning

confidence: 67%

Parasite-mediated heterozygote advantage in an outbred songbird population

MacDougall‐Shackleton

Derryberry

Foufopoulos

et al. 2005

Biol. Lett.

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Coevolution with parasites is thought to maintain genetic diversity in host populations. However, while there are sound theoretical reasons to expect heterozygosity and parasite resistance to be related, this pattern has generally been shown only in inbred laboratory and island populations. This leaves doubt as to whether parasitemediated selection for genetic diversity is in fact a general process. Here we show that haematozoan parasite load is linked to two complementary measures of microsatellite variability in an outbred population of mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) for which we know that parasites reduce fitness. Moreover, each of the genetic measures predicts a subtly different aspect of parasitism. Microsatellite heterozygosity is related to an individual's risk of parasitism, and mean d 2 (a broader, more long-term measure of parental relatedness) to the severity of infection among parasitized individuals.

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Section: Discussionmentioning

confidence: 67%

Parasite-mediated heterozygote advantage in an outbred songbird population

MacDougall‐Shackleton

Derryberry

Foufopoulos

et al. 2005

Biol. Lett.

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“…In two additional cases, the natural immigration of a few individuals into inbred populations of the Scandinavian wolf (Canis lupus) and Mandarte Island song sparrow (Melospiza melodia) resulted in genetic rescue [5,7]. The arrival of a single immigrant was associated with increased population growth for Scandinavian wolves, and the Mandarte Island song sparrow population exhibited higher fitness after immigration in the F 1 generation.…”

Section: Introductionmentioning

confidence: 98%

“…Genetic rescue, in which the introduction of one or more unrelated individuals into an inbred population results in an increase of vital rates, is expected to mitigate inbreeding depression (genetic load, see [3]) and other detrimental effects of inbreeding. The effects of genetic rescue have been observed in the wild on several occasions [3][4][5][6][7][8][9]. In four cases, genetic rescue was associated with human-mediated translocations of relatively large numbers of individuals.…”

Section: Introductionmentioning

confidence: 99%

“…The arrival of a single immigrant was associated with increased population growth for Scandinavian wolves, and the Mandarte Island song sparrow population exhibited higher fitness after immigration in the F 1 generation. However, in later generations in both examples, the populations experienced lowered fitness [5,7]. Apart from these cases, the effects of genetic rescue in wild populations are essentially unknown.…”

Section: Introductionmentioning

confidence: 99%

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Genomic sweep and potential genetic rescue during limiting environmental conditions in an isolated wolf population

et al. 2011

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Genetic rescue, in which the introduction of one or more unrelated individuals into an inbred population results in the reduction of detrimental genetic effects and an increase in one or more vital rates, is a potentially important management tool for mitigating adverse effects of inbreeding. We used molecular techniques to document the consequences of a male wolf ( Canis lupus ) that immigrated, on its own, across Lake Superior ice to the small, inbred wolf population in Isle Royale National Park. The immigrant's fitness so exceeded that of native wolves that within 2.5 generations, he was related to every individual in the population and his ancestry constituted 56 per cent of the population, resulting in a selective sweep of the total genome. In other words, all the male ancestry (50% of the total ancestry) descended from this immigrant, plus 6 per cent owing to the success of some of his inbred offspring. The immigration event occurred in an environment where space was limiting (i.e. packs occupied all available territories) and during a time when environmental conditions had deteriorated (i.e. wolves' prey declined). These conditions probably explain why the immigration event did not obviously improve the population's demography (e.g. increased population numbers or growth rate). Our results show that the beneficial effects of gene flow may be substantial and quickly manifest, short-lived under some circumstances, and how the demographic benefits of genetic rescue might be masked by environmental conditions.

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“…A number of empirical studies on a diverse array of animals have found outbreeding depression within animal populations (Caenorhabditis elegans: Dolgin et al, 2007;bark beetles: Peer and Taborsky, 2005; ornate dragon lizard: LeBas, 2002; song sparrow: Marr et al, 2002), sometimes in conjunction with inbreeding depression (humans: Helgason et al, 2008;Arabian oryx: Marshall and Spalton, 2000;fish: Neff, 2004;Daphnia: de Meester, 1993). When both inbreeding and outbreeding depression are taken into account, it seems logical that there should be a preference for mating partners that are moderately different from oneself, which would constitute the optimal outbreeding distance (Price and Waser, 1979;Bateson, 1983).…”

Section: Introductionmentioning

confidence: 99%

Outbreeding and possibly inbreeding depression in a pollinating fig wasp with a mixed mating system

et al. 2009

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Mixed mating systems are somewhat of an enigma as most models predict that organisms should either inbreed when inbreeding depression is low, or outbreed when inbreeding depression is high. Many wasps mix routine inbreeding with a little random mating. This random mating is most common when all local sibmating opportunities are exhausted and dispersal is the only way males can further increase their fitness. The males of the pollinating fig wasp, Platyscapa awekei, are slightly different in that they disperse before all sibmating opportunities have been exhausted. To see if this is a response to inbreeding depression we quantify inbreeding depression by comparing females' life time reproductive success to their heterozygosity at multiple microsatellite loci. We find that a female wasp's heterozygosity is an accurate predictor of her inbreeding coefficient and that P. awekei females actually seem to suffer from outbreeding depression and possibly from a little inbreeding depression. Male dispersal is thus not a means to effect the optimal mating system, but more likely a mechanism to reduce competition among brothers. The number of mature offspring a female produces depends on her own heterozygosity and not on that of the offspring, and may be determined by egg and gall quality.

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Heterosis and Outbreeding Depression in Descendants of Natural Immigrants to an Inbred Population of Song Sparrows (Melospiza Melodia)

Cited by 72 publications

References 80 publications

Parasite-mediated heterozygote advantage in an outbred songbird population

Parasite-mediated heterozygote advantage in an outbred songbird population

Genomic sweep and potential genetic rescue during limiting environmental conditions in an isolated wolf population

Outbreeding and possibly inbreeding depression in a pollinating fig wasp with a mixed mating system

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