Inbreeding: One word, several meanings, much confusion

Templeton, Alan R.; Read, Bruce

doi:10.1007/978-3-0348-8510-2_9

Cited by 131 publications

(75 citation statements)

References 20 publications

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“…This is probably a common genetic scenario in populations for which a program for the preservation of their genetic variability is being designed and should be taken into account to carefully conserve the genetic background of the founder individuals. In the wild, Tempelton and Read (1994) reported similar behaviour than that we found in the Xalda sheep. For these authors this can be expected in finite populations with separate sexes because of random differences in allele frequency between sexes.…”

Section: Discussionsupporting

confidence: 86%

Relationship between genealogical and microsatellite information characterizing losses of genetic variability: Empirical evidence from the rare Xalda sheep breed

Álvarez

Royo

Gutiérrez³

et al. 2008

Livestock Science

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Preservation of rare genetic stocks requires continual monitoring of populations to avoid losses of genetic variability. Genetic variability can be described using genealogical and molecular parameters characterizing variation in allelic frequencies over time and providing interesting information on differentiation that occurred after the foundation of a conservation program. Here we analyze the pedigree of the rare Xalda sheep breed (1851 individuals) and the polymorphism of 14 microsatellites in 239 Xalda individuals. Individuals were assigned to a base population (BP) or 4 different cohorts (from C1 to C4) according to their pedigree information. Genetic parameters were computed at a genealogical and molecular level, namely inbreeding (F), observed (H o ) and expected (H e ) heterozygosity, individual coancestry coefficients (f and f m ), average relatedness (AR), mean molecular kinship (Mk), average number of allele per locus (A), effective number of ancestors (f a ), effective population size (N e and N e(m) ) and founder genome equivalents (N g and N g(m) ). In general, the computed parameters increased with pedigree depth from BP to C4, especially for the genealogical information and molecular coancestry-based parameters (f m , Mk and N g(m) ). However, H o and H e showed the highest values for C1 and the molecular heterozygote deficiency within population (F IS(m) ) showed the lowest value for C1, thus indicating that loss of genetic variability occurs very soon after the implementation of conservation strategies. Although no genealogical or molecular parameters are sufficient by themselves for monitoring populations at the beginning of a conservation program, our data suggests that coancestry-based parameters may be better criteria than those of inbreeding or homozygosity because of the rapid and strong correlation established between f and f (m) . However, the obtaining of molecular information in well-established conservation programs could not be justified, at least in economic terms.

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Section: Discussionsupporting

confidence: 86%

Relationship between genealogical and microsatellite information characterizing losses of genetic variability: Empirical evidence from the rare Xalda sheep breed

Álvarez

Royo

Gutiérrez³

et al. 2008

Livestock Science

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“…We estimated the retained genetic diversity (GD) as GD~1{average MK ð Þ Thus, the current population has retained 95.8% of the genetic diversity of the population from which it was derived (i.e., the population 2 horse-generations ago). The loss of 4.2% of diversity over this time equates to an eigenvalue effective population size (Templeton and Read 1994) of 23, or approximately 16% of the census number. We estimated the future loss of genetic diversity using…”

Section: Analyses Using the Pedigreementioning

confidence: 99%

Pedigrees and the Study of the Wild Horse Population of Assateague Island National Seashore

et al. 2010

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Recently, a number of papers have addressed the use of pedigrees in the study of wild populations, highlighting the value of pedigrees in conservation management. We used pedigrees to study the horses (Equus caballus) of Assateague Island National Seashore, Maryland, USA, one of a small number of free-ranging animal populations that have been the subject of long-term studies. This population grew from 28 in 1968 to 175 in 2001, causing negative impacts on the island ecosystem. To minimize these effects, an immunocontraception program was instituted, and horse numbers are slowly decreasing. However, there is concern that this program may negatively affect the genetic health of the herd. We found that although mitochondrial DNA diversity is low, nuclear diversity is comparable to that of established breeds. Using genetic data, we verified and amended maternal pedigrees that had been primarily based on behavioral data and inferred paternity using genetic data along with National Park Service records of the historic ranges of males. The resulting pedigrees enabled us to examine demography, founder contributions, rates of inbreeding and loss of diversity over recent generations, as well as the level of kinship among horses. We then evaluated the strategy of removing individuals (using nonlethal means) with the highest mean kinship values. Although the removal strategy increased the retained diversity of founders and decreased average kinship between individuals, it disproportionately impacted sizes of the youngest age classes. Our results suggest that a combined strategy of controlled breeding and immunocontraception would be more effective than removing individuals with high mean kinships in preserving the long-term health and viability of the herd.

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“…The concern of the low allele variation is that it if continues diminishing, eventually over generations the levels of homozygosity and inbreeding will gradually increase [10,13,50] by the fact that the current population has a small population size, a situation that could increase the extinction risk in M. albiflora.…”

Section: Discussionmentioning

confidence: 99%

“…In these taxa, the lowest population genetic diversity levels are expected [9][10][11], and many study cases confirm such predictions (e.g., Table 5 [12], Table 1 [6]). These low levels of genetic diversity are explained by the effects of genetic drift, which bring out a severe loss of allele number in small populations [10,13]. Eventually, these extant alleles will have a common ancestor causing high levels of inbreeding and homozygosity [13].…”

Section: Introductionmentioning

confidence: 99%

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Genetics and Conservation of Plant Species of Extremely Narrow Geographic Range

2016

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Abstract:The endemic plant species with extremely narrow geographical range (<100 km 2 ) often have few populations of small size and tend to be more vulnerable to extinction by genetic drift and inbreeding effects. For these species, we tested if intraspecific genetic diversity can be applied to identify conservation priorities. The biological model was Mammillaria albiflora-a Mexican cactus that numbers~1000 individuals distributed in four nearby patches covering 4.3 km 2 . A total of 96 individuals were genotyped with 10 microsatellite loci to describe the genetic substructure and diversity. There is significant population substructure: the genetic diversity is distributed in three genetic neighbors and varies among the patches, the genotypes are not randomly distributed and three genetic barriers restrict the gene flow. The current population size is 15 times smaller than in the past. The restricted gene flow and genetic drift are the processes that have shaped population substructure. To conserve the genetic diversity of this cactus we recommend that two patches, which are not private property, be legally protected; to include M. albiflora in the Red List Species of Mexico in the category of extinction risk; and a legal propagation program may help to diminish the illegal harvesting.

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Inbreeding: One word, several meanings, much confusion

Cited by 131 publications

References 20 publications

Relationship between genealogical and microsatellite information characterizing losses of genetic variability: Empirical evidence from the rare Xalda sheep breed

Relationship between genealogical and microsatellite information characterizing losses of genetic variability: Empirical evidence from the rare Xalda sheep breed

Pedigrees and the Study of the Wild Horse Population of Assateague Island National Seashore

Genetics and Conservation of Plant Species of Extremely Narrow Geographic Range

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