Genetic Structure of Populations of the Mediterranean Mouflon (Ovis gmelini)

Petit, Éric; Aulagnier, Stéphane; Bon, Richard; Dubois, Michel; Crouau‐Roy, Brigitte

doi:10.2307/1382898

Cited by 25 publications

(29 citation statements)

References 35 publications

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“…The pure Saaremaa panmictic populations appeared unique. The strong effect of subdivision into flocks differs from earlier studies in cattle and mouflon (Petit et al, 1997;Casellas et al, 2004). Although the small number of studied individuals in these populations may exaggerate genetic distances (Paetkau et al, 1999), this bias is unlikely to affect strongly the grouping on the first axes of the PCoA.…”

Section: Distribution Of Genetic Variationcontrasting

confidence: 66%

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Unfolding of population structure in Baltic sheep breeds using microsatellite analysis

Tapio

Grīslis

et al. 2005

Heredity

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Studies of domestic animals are performed on breeds, but a breed does not necessarily equate to a genetically defined population. The division of sheep from three native and four modern Baltic sheep breeds was studied using 21 microsatellite loci and applying a Bayesian clustering method. A traditional breed-wise approach was compared to that relying on the pattern of molecular diversity. In this study, a breed was found to be inconsistent with a distinct genetic population for three reasons: (i) a lack of differentiation between modern Baltic breeds, since the majority of the studied sheep formed a single population; (ii) the presence of individuals of foreign ancestry within the breed; and (iii) an undefined local Saaremaa sheep was referred to as a breed, but was shown to consist of separate populations. In the breed-wise approach, only the clearly distinct Ruhnu sheep demonstrated low within-breed variation, although the newly identified Saaremaa populations also have low variability. Providing adequate management recommendations for the Saaremaa sheep is not possible without further studies, but the potential harmful effects of inbreeding in the Ruhnu sheep could be reduced through the use of two genetically related Saaremaa populations. In other breeds, excessive crossing appears to be a larger concern than inbreeding. Assigning individuals into populations based on the pattern of genetic diversity offers potentially unbiased means of elucidating the genetic population structure of species. Combining these genetic populations with phenotypic and aetiological data will enable formulation of the most informed recommendations for gene resource management. Heredity (2005) 94, 448-456.

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Section: Distribution Of Genetic Variationcontrasting

confidence: 66%

“…Contrary to modern breeds, the old undefined local populations can consist of genetically differentiated flocks as previously reported in sheep (Petit et al, 1997;Tapio et al, 2003). The subdivision, as supported by the deviations from HWE and genotypic linkage disequilibrium, was evident for the Estonian Saaremaa sheep.…”

Section: Discussionmentioning

confidence: 58%

Unfolding of population structure in Baltic sheep breeds using microsatellite analysis

Tapio

Grīslis

et al. 2005

Heredity

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“…¼ 39.077.0 Ha) relative to the size of the island (that is 650 Ha). Furthermore, male and female mouflon in Europe are known to be philopatric (Dubois et al, 1993(Dubois et al, , 1995Petit et al, 1997; see also Martins et al, 2002) and to reproduce in their natal area (Dubois et al, 1995). Coltman et al (2003) have also found weak genetic structure on an insular population of sheep.…”

Section: R Kaeuffer Et Almentioning

confidence: 99%

Detecting population structure using STRUCTURE software: effect of background linkage disequilibrium

Kaeuffer¹,

Réale²,

Coltman³

et al. 2007

Heredity

103

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STRUCTURE is the most widely used clustering software to detect population genetic structure. The last version of this software (STRUCTURE 2.1) has been enhanced recently to take into account the occurrence of linkage disequilibrium (LD) caused by admixture between populations. This last version, however, still does not consider the effects of strong background LD caused by genetic drift, and which may cause spurious results. STRUCTURE authors have, therefore, suggested a rough threshold value of the distance (1.0 cM) between two loci below which the pair of loci should not be used. Because of the sensitiveness of LD to demographic events, the distance between loci is not always a good indicator of the strength of LD. In this study, we examine the link between genomic distance and the strength of the correlation between loci (r LD ) in a free-ranging population of mouflon (Ovis aries), and we present an empirical test of effect of r LD on the clustering results provided by the linkage model in STRUCTURE. We showed that a high r LD value increases the probability of detecting spurious clustering. We propose to use r LD as an index to base a decision on whether or not to use a pair of loci in a clustering analysis. Keywords: STRUCTURE software; linkage disequilibrium; population structure; clustering Introduction STRUCTURE (Pritchard et al., 2000) is the most widely used clustering software applied to detect population genetic structure, with more than 1000 citations for its first version (Pritchard et al., 2000) and more than 170 citations for its recent enhanced version (Falush et al., 2003) (source: ISI Web of Science database). STRUCTURE generates clusters based on both transient HardyWeinberg disequilibrium (HWD) and linkage disequilibrium (LD) caused by admixture between populations. The program works by clustering individuals in groups, where both linkage and HWD are minimized, and therefore, the presence of LD in the data improves clustering results (Falush et al., 2003). On the other hand, 'strong' LD or departure from Hardy-Weinberg equilibrium could lead to an overestimation of the number of clusters detected (Falush et al., 2003).STRUCTURE deals with two kinds of LD: the first is mixture LD, which occurs across loci even if they are unlinked due to the correlation of allele frequencies 'because individuals with a large component of ancestry in population k have an excess of alleles that are common in k' (Falush et al., 2003). The second is admixture LD, which is 'the correlation that arises between linked markers in recently admixed populations ' (Pritchard and Wen, 2004). This LD occurs because markers are on the same 'chunk' of chromosome that derives from an ancestral population. The 'admixture model' implemented in the latest version of STRUCTURE (STRUCTURE 2.1;Falush et al., 2003) combines admixture LD with map distances between markers to improve clustering results. Falush et al. (2003) defined a third kind of LD: the background LD measured between syntenous loci separated by few cM. Background...

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“…The higher male than female dispersal suggested by differences in genetic structure and numbers of dispersers within the Norwegian population will therefore, depending on the mating success of the dispersers, in the next generation translate to gene flow between the subpopulations. Genetic differentiation from polygony and limitations to gene flow by philopatry among social groups (Chesser, 1991b;Chesser, 1991a) have been reported as fine-scale genetic structure in several ungulates like Soay sheep (Ovis aries; Coltman et al, 2003), Mediterranean muflon (Ovis gmelini; Petit et al, 1997) and White-tailed deer (Odocoileus virginianus; Mathews & Porter, 1993;Purdue et al, 2000), and red deer (Nussey et al, 2005;Frantz et al, 2008). On a scale of a few kilometers, malebiased gene flow has been suggested from a much weaker genetic structure in nuclear microsatellite markers than in maternally inherited mitochondrial DNA among red deer management blocks on the Scottish island of Rhum (Nussey et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…Theoretical studies show that philopatry in concert with polygony may involve small scale genetic differentiation among social groups (Chesser, 1991b;Chesser, 1991a), which may have important evolutionary consequences for kin and localized selection (Coltman et al, 2003). In many ungulate species polygony and philopatry thus involves a pronounced fine-scale genetic structure (Mathews & Porter, 1993;Petit et al 1997;Purdue et al, 2000;Coltman et al, 2003;Nussey et al, 2005). Sex-biased dispersal at the subpopulation and meta-population levels has however been poorly documented (Prugnolle & de Meeus, 2002), but has recently been reported for turtles (Bowen & Karl, 2007) and bats (Chen et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Sex-biased dispersal in a northern ungulate population

Haanes

Røed

Rosef

2011

Ran

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Abstract:In most mammals dispersal is male-biased and in many polygynous ungulates female philopatry and matrilineal grouping involve small-scale genetic structure. We have through sex-related differences in microsatellite allele distribution addressed sex-biased dispersal in a spatially expanding northern ungulate population. The Norwegian red deer population (Cervus elaphus atlanticus) has the last hundred years grown substantially and expanded spatially after a major decline from 300 to 100 years ago. Previous Bayesian analyses suggest a present division of genetic variation into five geographically separated subpopulations. Among these subpopulations the overall F st values were 0.067 (SE=0.014) for males and 0.094 (SE=0.017) for females. Pairwise F st values were significantly higher for females than males, demonstrating a stronger genetic structure among females, and that dispersal has been lower in females than males. Accordingly, a higher number of male than female first generation dispersers were identified among the five subpopulations using Bayesian assignment with prior population information, but significantly so only with relaxed stringency levels of assignment. The identified male-biased dispersal distances varied from 30 to 300 kilometers suggesting male biased dispersal on a large scale in red deer.

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Genetic Structure of Populations of the Mediterranean Mouflon (Ovis gmelini)

Cited by 25 publications

References 35 publications

Unfolding of population structure in Baltic sheep breeds using microsatellite analysis

Unfolding of population structure in Baltic sheep breeds using microsatellite analysis

Detecting population structure using STRUCTURE software: effect of background linkage disequilibrium

Sex-biased dispersal in a northern ungulate population

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