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 The Effects of Hill-Robertson Interference Between Weakly Selected Mutations on Patterns of Molecular Evolution and Variation

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 929-944 ◽  
Author(s):  
Gilean A T McVean ◽  
Brian Charlesworth
Keyword(s):  
Codon Bias ◽  
Molecular Adaptation ◽  
Weak Selection ◽  
Multiple Loci ◽  
Locus Model ◽  
Fitness Consequences ◽  
Novel Variants ◽  
Population Sizes ◽  
The Hill ◽  
Reversible Mutation

Abstract Associations between selected alleles and the genetic backgrounds on which they are found can reduce the efficacy of selection. We consider the extent to which such interference, known as the Hill-Robertson effect, acting between weakly selected alleles, can restrict molecular adaptation and affect patterns of polymorphism and divergence. In particular, we focus on synonymous-site mutations, considering the fate of novel variants in a two-locus model and the equilibrium effects of interference with multiple loci and reversible mutation. We find that weak selection Hill-Robertson (wsHR) interference can considerably reduce adaptation, e.g., codon bias, and, to a lesser extent, levels of polymorphism, particularly in regions of low recombination. Interference causes the frequency distribution of segregating sites to resemble that expected from more weakly selected mutations and also generates specific patterns of linkage disequilibrium. While the selection coefficients involved are small, the fitness consequences of wsHR interference across the genome can be considerable. We suggest that wsHR interference is an important force in the evolution of nonrecombining genomes and may explain the unexpected constancy of codon bias across species of very different census population sizes, as well as several unusual features of codon usage in Drosophila.

scholarly journals Haplotype analysis on correlation between transcription factor 7-like 2 gene polymorphism and breast cancer risk

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yang Wang ◽  
Xiaojuan Men ◽  
Yongxue Gu ◽  
Huidong Wang ◽  
Zhicai Xu
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Logistic Regression ◽  
Abdominal Obesity ◽  
Haplotype Analysis ◽  
Environment Interaction ◽  
Nucleotide Polymorphisms ◽  
Chinese Han ◽  
Locus Model ◽  
Gene Environment

Abstract Background Up to now, limited researches focused on the association between transcription factor 7-like 2 gene (TF7L2) gene single nucleotide polymorphisms (SNPs) and breast cancer (BC) risk. The aim of this study was to evaluate the associations between TF7L2 and BC risk in Chinese Han population. Methods Logistic regression model was used to test the correlation between polymorphisms and BC risk. Strength of association was evaluated by odds ratio (OR) and 95% confidence interval (CI). Generalized multifactor dimensionality reduction (GMDR) was applied to analyze the SNP-SNP and gene-environment interaction. Results Logistic regression analysis indicated that the BC risk was obviously higher in carriers of rs1225404 polymorphism C allele than that in TT genotype carriers (TC or CC versus TT), adjusted OR (95%CI) =1.40 (1.09–1.72). Additionally, we also discovered that people with rs7903146- T allele had an obviously higher risk of BC than people with CC allele (CT or TT versus CC), adjusted OR (95%CI) =1.44 (1.09–1.82). GMDR model was used to research the effect of interaction among 4 SNPs and environmental factors on BC risk. We discovered an important two-locus model (p = 0.0100) including rs1225404 and abdominal obesity, suggesting a potential gene–environment correlation between rs1225404 and abdominal obesity. In general, the cross-validation consistency of two-locus model was 10 of 10, and the testing accuracy was 0.632. Compared with subjects with normal waist circumference (WC) value and rs1225404 TT genotype, abdominal obese subjects with rs1225404 TC or CC genotype had the highest BC risk. After covariate adjustment, OR (95%CI) was 2.23 (1.62–2.89). Haplotype analysis indicated that haplotype containing rs1225404-T and rs7903146-C alleles were associated with higher BC risk. Conclusions C allele of rs1225404 and T allele of rs7903146, interaction between rs1225404 and abdominal obesity, rs1225404-T and rs7903146-C haplotype were all related to increased BC risk.

Genetic Models of Affective Disorder: Application to Twin Data

1980 ◽  
Vol 29 (4) ◽  
pp. 289-294 ◽  
Author(s):  
Miron Baron
Keyword(s):  
Affective Disorder ◽  
Affective Disorders ◽  
Monozygotic Twins ◽  
Threshold Models ◽  
Twin Data ◽  
Bipolar Illness ◽  
Major Locus ◽  
Unipolar Disorder ◽  
Locus Model ◽  
Multiple Threshold

Twin data on bipolar and unipolar affective disorders are analyzed by multiple threshold models of inheritance. The two illness types are represented in the models on a continuum of genetic–environmental liability in which bipolar illness has a higher liability threshold than unipolar disorder. Autosomal single major locus model provides an acceptable fit to observed concordance rates in monozygotic twins. The multifactorial-polygenic model is rejected.

Two-disease locus model: Sib pair method using information on both HLA and Gm

1986 ◽  
Vol 3 (5) ◽  
pp. 343-356 ◽  
Author(s):  
M. Hélène Dizier ◽  
Françoise Clerget-Darpoux ◽  
D. C. Rao
Keyword(s):  
Disease Locus ◽  
Locus Model ◽  
Pair Method

scholarly journals Event-related potential evidence for a dual-locus model of global/local processing

2010 ◽  
Vol 10 (7) ◽  
pp. 91-91 ◽  
Author(s):  
K. Dalrymple ◽  
A. Kingstone ◽  
T. Handy
Keyword(s):  
Event Related Potential ◽  
Local Processing ◽  
Locus Model

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

The inheritance of flowering time in Townsville stylo (Stylosanthes humilis)

1976 ◽  
Vol 27 (6) ◽  
pp. 825 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Flowering Time ◽  
Dominant Gene ◽  
Diallel Cross ◽  
Early Flowering ◽  
Multiple Alleles ◽  
Locus Model ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Maturity Groups ◽  
Early Flowering Phenotype

The inheritance of flowering time was studied in F1, F2 and F3 populations derived from a diallel cross among nine naturalized Australian lines of Townsville stylo (Stylosnnthes humilis) and in F1 and F2 populations from a small number of crosses between naturalized Australian lines and introductions from Mexico and Brazil. Strong dominance for lateness of flowering was observed in both the (Australian x Australian) and the (Australian x Mexican/Brazilian introductions) crosses, and some F2 and F3 progenies included small numbers of extremely early plants, flowering up to 55 days earlier than the earliest parent. The flowering time distributions of the (Australian x Australian) crosses could be explained by a three-locus model with multiple alleles at two loci. Proposed genotypes for the four maturity groups are as follows: late, LLM2M2EE; late-midseason, LLmmEE; mid-season, l2l2M2M2EE; early, l1l1M1M1EE; very early, LLM2M2ee. Only one major dominant gene for lateness of flowering could be detected from the distribution of the two (Australian x introduced line) F2 populations, but the segregation of extremely early types and the low recovery of the early-flowering phenotype suggested that other gene loci were segregating.

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