Evidence for a wahlund effect in a unique breton community, the bigoudens

1986 ◽  
Vol 1 (2) ◽  
pp. 157-165 ◽  
Author(s):  
D. Salmon ◽  
P. Youinou ◽  
Ph. Rouger ◽  
J. Jouquan ◽  
G. Le Menn ◽  
...  
Keyword(s):  
Wahlund Effect

scholarly journals  Allele frequency in loci which control coat colours in Hucul horse population

2012 ◽  
Vol 57 (No. 4) ◽  
pp. 178-186 ◽  
Author(s):  
A. Stachurska ◽  
A. Brodacki ◽  
J. Grabowska
Keyword(s):  
Genetic Structure ◽  
Allele Frequency ◽  
Global Strategy ◽  
Recessive Allele ◽  
Genotype Distribution ◽  
Horse Population ◽  
Wahlund Effect ◽  
Animal Genetic Resources ◽  
Genotype Frequencies ◽  
Its Gene

The objective of the study was to determine the frequency of alleles which produce coat colours in Hucul horse population in Poland. The breed is included in the Global Strategy for Management of Farm Animal Genetic Resources, hence its gene pool should remain in unaltered state. Huculs are bay, black, blue dun, yellow dun, tobiano, and chestnut. Grey and chestnut Huculs have always been undesirable. The material consisted of all 1022 matings which resulted in subpopulations recorded in Studbook volumes. The recessive allele frequency was estimated as the square root of recessive genotype frequencies in ASIP (A), MC1R (E), DUN (D), KIT (To region), and STX17 (G) loci. The frequency in A and E loci in total parental generation was also estimated in test matings. Genotype distribution in the population was anticipated according to gamete frequency in sires and dams. Small Wahlund effect, F<sub>ST</sub>and &chi;<sup>2</sup> values for allele distributions show that division into subpopulations did not influence the population genetic structure significantly. Mean recessive allele frequency in A, E, D, To, and G loci amounted to 0.521, 0.115, 0.878, 0.929, and 0.997, respectively, and in A and E loci it was similar to that assessed in test matings. More bay horses and fewer D diluted horses appeared in offspring than expected. A, e, d, and To allele frequency showed a rising tendency. The genetic structure in Hucul population is not constant and does not comply strictly with the preservation aim. Bay, non-diluted, and tobiano horses are preferred. The linkage between MC1R and KIT loci can make the selection against e allele difficult. Breeders&rsquo; preferences may lead to undesired changes in the allele frequency. To avoid such risk, it is recommended to select horses strictly complying with the rules included in the breeding programme and mate the horses randomly from this aspect. &nbsp;

Isozyme diversity in large and isolated populations of Luma apiculata (Myrtaceae) in north-western Patagonia, Argentina

2005 ◽  
Vol 53 (8) ◽  
pp. 781 ◽  
Author(s):  
Mayra S. Caldiz ◽  
Andrea C. Premoli
Keyword(s):  
Genetic Variation ◽  
Isolated Populations ◽  
Isozyme Electrophoresis ◽  
Wahlund Effect ◽  
Rivers And Lakes ◽  
Large Populations ◽  
Vegetative Spread ◽  
Number Of Individuals ◽  
North Western ◽  
Isozyme Diversity

We evaluated the amount and distribution of genetic variation in large and small isolated populations of Luma apiculata (DC.) Burret (Myrtaceae) in north-western Patagonia. The hypothesis tested was that isolated smaller populations were more affected by drift and isolation than large stands. Higher genetic diversity was predicted in the latter. Fresh leaf material for isozyme electrophoresis was collected from 30 individuals in four isolated and two large and continuous stands (Quetrihue Peninsula and Punta Norte, Isla Victoria). Five subpopulations were sampled in both large stands, and in addition, three regeneration gaps in Punta Norte. Eleven loci were resolved; 91% were polymorphic in at least one population. Isolated and large populations had similar levels of genetic variation. Reduced observed heterozygosity and elevated inbreeding were measured in subpopulations and regeneration gaps within dense stands. Although small populations consist of a reduced number of individuals they are mostly coastal populations nearby rivers and lakes that may maintain considerable gene flow with other faraway populations counteracting the effects of drift. In addition to potential selfing, increased inbreeding within large populations and regeneration gaps may be due to an intra-population Wahlund effect from local seedling establishment and vegetative spread, resulting in clustered cohorts of similar genotypes.

The Wahlund Effect for the Two-Locus Model

1975 ◽  
Vol 109 (969) ◽  
pp. 565-570 ◽  
Author(s):  
Pomeroy Sinnock
Keyword(s):  
Wahlund Effect ◽  
Locus Model

scholarly journals Genetic diversity and population structure of Zackel sheep and other Hungarian sheep breeds

2015 ◽  
Vol 58 (2) ◽  
pp. 343-350 ◽  
Author(s):  
V. Neubauer ◽  
C. Vogl ◽  
J. Seregi ◽  
L. Sáfár ◽  
G. Brem
Keyword(s):  
Close Relationships ◽  
Data Cleaning ◽  
Genetic Distances ◽  
Null Alleles ◽  
High Genetic Variability ◽  
Sheep Breeds ◽  
Wahlund Effect ◽  
Expected Heterozygosity ◽  
Hardy Weinberg Equilibrium ◽  
The Individual

Abstract. More than 6000 samples of 18 different Hungarian sheep breeds were genotyped for 10 unlinked microsatellite loci. After data cleaning, 5434 sheep remained in the analysis. Some locus–breed combinations show deviation from Hardy–Weinberg equilibrium, possibly due to null alleles or the Wahlund effect. All breeds show high genetic variability; the lowest expected heterozygosity is that of the British Milksheep (He = 0.588). The Transylvanian Zackel has the highest expected heterozygosity (He = 0.790). It is also the least differentiated breed (Fst = 0.020). Pairwise genetic distances among breeds range from 0.021 between Hungarian Merino and both Mutton Merino and Transylvanian Zackel to greater than 0.105 between British Milksheep and all other breeds. The three Zackel populations – white, black, and Transylvanian Zackel – show small genetic distances among each other, with pairwise Fst values from 0.030 to 0.058. The Transylvanian Zackel tended to have close relationships to some other breeds too, probably due to its low differentiation. Given the individual genotypic information, a Bayesian analysis assigned individuals to breeds generally correctly.

Wahlund Effect

2001 ◽  
pp. 2127-2132
Author(s):  
M.A. Asmussen
Keyword(s):  
Wahlund Effect

Wahlund Effect

2016 ◽  
Author(s):  
Monica Nordberg ◽  
Douglas M. Templeton ◽  
Ole Andersen ◽  
John H. Duffus
Keyword(s):  
Wahlund Effect

Genetic variation within and among infrapopulations of the marine digenetic trematode Lecithochirium fusiforme

Parasitology ◽  
2003 ◽  
Vol 126 (5) ◽  
pp. 465-472 ◽  
Author(s):  
R. VILAS ◽  
E. PANIAGUA ◽  
M. L. SANMARTÍN
Keyword(s):  
Genetic Variation ◽  
Digenetic Trematode ◽  
Significant Linkage Disequilibrium ◽  
Polymorphic Loci ◽  
Wahlund Effect ◽  
Hardy Weinberg Equilibrium ◽  
Significant Deficit ◽  
Paratenic Hosts ◽  
Significant Linkage ◽  
Conger Conger

Allozyme markers were used to study genetic variation in Lecithochirium fusiforme within a natural population of Conger conger. Six of 16 enzyme-coding loci studied were found to be polymorphic. These loci were surveyed in 12 infrapopulations of adult flukes. High levels of genetic variation were detected (P=0·375); Ho=0·048; He=0·085). However, the population did not conform to Hardy-Weinberg expectations, as it showed a significant deficit of heterozygotes. L. fusiforme also exhibited low differentiation between infrapopulations (FST=0·064). Despite significant linkage disequilibrium at Pgm-1 and Pgm-2 (P<0·05), mating system does not appear to be the principal reason for the deficit of heterozygotes detected, because some polymorphic loci were in Hardy-Weinberg equilibrium. Association between FIS and FST statistics suggests the existence of the Wahlund effect. However, all infrapopulations showed a strong deficit of heterozygotes for most polymorphic loci (FIS=0·409). Detection of significant genetic differentiation among temporal samples and the existence of paratenic hosts in the life-cycle suggests the Wahlund effect, caused by the mixture of genetically distinct temporal samples in the infrapopulations. Occasional temporal gene flow also might explain the high estimated genetic polymorphism.

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