On Diversity

Weitzman, Martin L.

doi:10.2307/2118476

Cited by 502 publications

(398 citation statements)

References 0 publications

Supporting

Mentioning

380

Contrasting

Unclassified

Order By: Relevance

“…Results using the Weitzman approach (Weitzman, 1992 and1993) favored the Lac La Croix pony as having the greatest marginal loss (6.57%) of all the populations tested when removed from the data set and was followed closely by the Exmoor (6.06%) and Eriskay (5.66%) breeds. In contrast, the Welsh population was found to have the least marginal loss (1.65%), followed closely by the New Forest (2.18%) and Newfoundland-CDN population (2.23%).…”

Section: Resultsmentioning

confidence: 99%

“…Contributions of each population to overall genetic diversity was also assessed using marginal loss (Weitzman, 1992 and1993) and Nei's (1983) genetic distance as implemented in WEITZPRO (D'Arnoldi et al, 1998). In addition, the loss in genetic diversity from the data set was also assessed using the Petit et al's (1998) approach and molecular kinship analyses as proposed by Caballero and Toro (2002) and implemented in MOLKIN version 2 (Gutié rrez et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Further study will have to be conducted to determine the relationship of the Lac La Croix among both horse and pony breeds, as this breed was not consistently placed in the phylogenetic trees using the four genetic distances estimated. (Weitzman, 1992 and1993).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Genetic diversity and admixture among Canadian, Mountain and Moorland and Nordic pony populations

Prystupa

Juras

Cothran

et al. 2012

Animal

View full text Add to dashboard Cite

As part of the requirements of the Convention on Biological Diversity, Canada has been investigating the genetic diversity of its native equine and pony populations. Along with examining four indigenous Canadian equine populations (Canadian horse, Lac La Croix pony, Newfoundland pony and Sable Island population), another 10 Mountain and Moorland, three Nordic, four horse and two feral equine populations (thought to have influenced some pony breeds) were also investigated. In total, 821 individuals were genotyped at 38 microsatellite loci. Results of the analysis of molecular variance indicated that 13.3% of genetic diversity was explained by breed differences, whereas 84.6% and 2.1% of diversity came from within and among individuals, respectively. The average effective number of alleles and allelic richness was the lowest in the Eriskay (2.51 and 3.98) and Lac La Croix (2.83 and 4.01) populations, whereas it was highest in the New Forest (4.31 and 6.01) and Welsh (4.33 and 5.87) breeds, followed closely by the Newfoundland-CDN (4.23 and 5.86) population. Expected heterozygosities varied from 0.61 in the Lac La Croix to 0.74 in the Welsh and in Newfoundland. Observed heterozygosities ranged from 0.57 in the Exmoor and 0.58 in the Sable Island herd to 0.77 in the Kerry Bog and 0.76 in the New Forest breeds. Structure and admixture analyses revealed that the most likely number of clusters was 21, although some substructure was also observed when K 5 16, compared with the 24 predefined populations. Information gathered from this study should be combined with other available phenotypic and pedigree data to develop, or amend, a suitable conservation strategy for all populations examined.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Genetic diversity and admixture among Canadian, Mountain and Moorland and Nordic pony populations

Prystupa

Juras

Cothran

et al. 2012

Animal

View full text Add to dashboard Cite

show abstract

“…Following the Weitzman approach [53,54], the Reynolds genetic distances were used to compute marginal losses of genetic diversity. After transforming the genetic distance matrix into a distance matrix with ultrametric properties, a maximum likelihood tree was drawn using NTSYS [40].…”

Section: Computing Diversitymentioning

confidence: 99%

Genetic diversity measures of local European beef cattle breeds for conservation purposes

et al. 2001

View full text Add to dashboard Cite

-This study was undertaken to determine the genetic structure, evolutionary relationships, and the genetic diversity among 18 local cattle breeds from Spain, Portugal, and France using 16 microsatellites. Heterozygosities, estimates of Fst, genetic distances, multivariate and diversity analyses, and assignment tests were performed. Heterozygosities ranged from 0.54 in the Pirenaica breed to 0.72 in the Barrosã breed. Seven percent of the total genetic variability can be attributed to differences among breeds (mean F st = 0.07; P < 0.01). Five different genetic distances were computed and compared with no correlation found to be significantly different from 0 between distances based on the effective size of the population and those which use the size of the alleles. The Weitzman recursive approach and a multivariate analysis were used to measure the contribution of the breeds diversity. The Weitzman approach suggests that the most important breeds to be preserved are those grouped into two clusters: the cluster formed by the Mirandesa and Alistana breeds and that of the Sayaguesa and Tudanca breeds. The hypothetical extinction of one of those clusters represents a 17% loss of diversity. A correspondence analysis not only distinguished four breed groups but also confirmed results of previous studies classifying the important breeds contributing to diversity. In addition, the variation between breeds was sufficiently high so as to allow individuals to be assigned to their breed of origin with a probability of 99% for simulated samples.local beef cattle breeds / microsatellite / genetic diversity

show abstract

“…Molecular techniques can be used to assess within-population genetic diversity and between-population differentiation and, therefore, make inferences on the degree of uniqueness of the analyzed populations. A number of approaches for quantifying genetic diversity have been proposed as tools for decision making in genetic conservation programs, including phylogenetic-like approaches such as that by Weitzman (1992) and Thaon d'Arnoldi et al (1998), those focusing on the maximization of the Nei's (1987) gene diversity (Eding and Meuwissen, 2001;Caballero and Toro, 2002) or the average number of alleles per locus (Petit et al, 1998; a These authors contributed equally to this work and shall share the first authorship.…”

Section: Introductionmentioning

confidence: 99%

Assessing priorities for conservation in Tuscan cattle breeds using microsatellites

Bozzi¹,

Álvarez

Crovetti³

et al. 2012

Animal

View full text Add to dashboard Cite

Preservation of rare genetic stocks requires assessment of within-population genetic diversity and between-population differentiation to make inferences on their degree of uniqueness. A total of 194 Tuscan cattle (44 Calvana, 35 Chianina, 25 Garfagnina, 31 Maremmana, 31 Mucca Pisana and 28 Pontremolese) individuals were genotyped for 34 microsatellite markers. Moreover, 56 samples belonging to Argentinean Creole and Asturiana de la Montañ a cattle breeds were used as an outgroup. Genetic diversity was quantified in terms of molecular coancestry and allelic richness. STRUCTURE analyses showed that the Tuscan breeds have well-differentiated genetic backgrounds, except for the Calvana and Chianina breeds, which share the same genetic ancestry. The between-breed Nei's minimum distance (D m ) matrices showed that the pair Calvana-Chianina was less differentiated (0.049 6 0.006). The endangered Tuscan breeds (Calvana, Garfagnina, Mucca Pisana and Pontremolese) made null or negative contributions to diversity, except for the Mucca Pisana contribution to allelic richness (C T 5 1.8%). The Calvana breed made null or negative within-breed contributions (f¯W 5 0.0%; C W 5 20.4%). The Garfagnina and Pontremolese breeds made positive contributions to between-breed diversity but negative and high within-breed contributions, thus suggesting population bottleneck with allelic losses and increase of homozygosity in the population. Exclusion of the four endangered Tuscan cattle breeds did not result in losses in genetic diversity (f¯T 5 20.7%; C T 5 21.2%), whereas exclusion of the non-endangered breeds (Chianina and Maremmana) did (f¯T 5 2.1%; C T 5 3.9%); the simple exclusion of the Calvana breed from the former group led to losses in genetic diversity (f¯T 5 0.47%; C T 5 2.34%), indicating a diverse significance for this breed. We showed how quantifying both within-population diversity and between-population differentiation in terms of allelic frequencies and allelic richness provides different and complementary information on the genetic backgrounds assessed and may help to implement priorities and strategies for conservation in livestock.

show abstract

On Diversity

Cited by 502 publications

References 0 publications

Genetic diversity and admixture among Canadian, Mountain and Moorland and Nordic pony populations

Genetic diversity and admixture among Canadian, Mountain and Moorland and Nordic pony populations

Genetic diversity measures of local European beef cattle breeds for conservation purposes

Assessing priorities for conservation in Tuscan cattle breeds using microsatellites

Contact Info

Product

Resources

About