scholarly journals Niche specificity, polygeny, and pleiotropy in herbivorous insects

2021 ◽  
Author(s):  
Nate B. Hardy ◽  
Matt Forister
Keyword(s):  
Population Genetic ◽  
Host Preference ◽  
Genetic Models ◽  
Herbivorous Insects ◽  
Host Use ◽  
Antagonistic Pleiotropy ◽  
Quantitative Genetic ◽  
Polygenic Trait ◽  
Parasite Populations

AbstractWhy do herbivorous insects tend to be host specialists? Population genetic models predict specialization when there is antagonistic pleiotropy at a gene for host-use performance. But empirically, host-use performance is governed by many genetic regions, and antagonistic pleiotropy is rare. Here, we use individual-based quantitative genetic simulations to investigate the role of pleiotropy in the evolution of host-use specialization when host-use performance is polygenic. We find that if host-preference is allowed to evolve without cost, parasite populations tend to evolve host-use specialization even without pleiotropy; thus, it would seem that for a polygenic trait, the benefit of maintaining adaptive combinations of conditionally-neutral alleles suffices to drive specialization. But if there is a fecundity cost for host-preference, or if host patches are demographically volatile, host-use generalists evolve, even with high levels of pleiotropy. In sum, if pleiotropy is much more pervasive than has been observed in nature, our simulations show that it could play a role in driving the evolution of polygenic specialization. But pleiotropy is not necessary, and even when it is extensive, selection can favor generalist genotypes.

The role of the poisson progeny distribution in population genetic models

1968 ◽  
Vol 2 (1-2) ◽  
pp. 11-17 ◽  
Author(s):  
Samuel Karlin ◽  
James McGregor
Keyword(s):  
Population Genetic ◽  
Genetic Models

scholarly journals Disentangling selection on genetically correlated polygenic traits using whole-genome genealogies

2020 ◽  
Author(s):  
Aaron J. Stern ◽  
Leo Speidel ◽  
Noah A. Zaitlen ◽  
Rasmus Nielsen
Keyword(s):  
Dna Sequence ◽  
Population Genetic ◽  
Sequence Data ◽  
Directional Selection ◽  
Likelihood Method ◽  
Correlated Response ◽  
Correlated Traits ◽  
Dna Sequence Data ◽  
Polygenic Traits ◽  
Polygenic Trait

AbstractWe present a full-likelihood method to estimate and quantify polygenic adaptation from contemporary DNA sequence data. The method combines population genetic DNA sequence data and GWAS summary statistics from up to thousands of nucleotide sites in a joint likelihood function to estimate the strength of transient directional selection acting on a polygenic trait. Through population genetic simulations of polygenic trait architectures and GWAS, we show that the method substantially improves power over current methods. We examine the robustness of the method under uncorrected GWAS stratification, uncertainty and ascertainment bias in the GWAS estimates of SNP effects, uncertainty in the identification of causal SNPs, allelic heterogeneity, negative selection, and low GWAS sample size. The method can quantify selection acting on correlated traits, fully controlling for pleiotropy even among traits with strong genetic correlation (|rg| = 80%; c.f. schizophrenia and bipolar disorder) while retaining high power to attribute selection to the causal trait. We apply the method to study 56 human polygenic traits for signs of recent adaptation. We find signals of directional selection on pigmentation (tanning, sunburn, hair, P=5.5e-15, 1.1e-11, 2.2e-6, respectively), life history traits (age at first birth, EduYears, P=2.5e-4, 2.6e-4, respectively), glycated hemoglobin (HbA1c, P=1.2e-3), bone mineral density (P=1.1e-3), and neuroticism (P=5.5e-3). We also conduct joint testing of 137 pairs of genetically correlated traits. We find evidence of widespread correlated response acting on these traits (2.6-fold enrichment over the null expectation, P=1.5e-7). We find that for several traits previously reported as adaptive, such as educational attainment and hair color, a significant proportion of the signal of selection on these traits can be attributed to correlated response, vs direct selection (P=2.9e-6, 1.7e-4, respectively). Lastly, our joint test uncovers antagonistic selection that has acted to increase type 2 diabetes (T2D) risk and decrease HbA1c (P=1.5e-5).

scholarly journals Linking Dynamical and Population Genetic Models of Persistent Viral Infection

2003 ◽  
Vol 162 (1) ◽  
pp. 14-28 ◽  
Author(s):  
John K. Kelly ◽  
Scott Williamson ◽  
Maria E. Orive ◽  
Marilyn S. Smith ◽  
Robert D. Holt
Keyword(s):  
Viral Infection ◽  
Population Genetic ◽  
Genetic Models ◽  
Persistent Viral Infection

Population Genetic Models

2018 ◽  
pp. 87-117
Author(s):  
John S. Buckleton ◽  
Duncan Taylor ◽  
James M. Curran ◽  
Jo-Anne Bright
Keyword(s):  
Population Genetic ◽  
Genetic Models

scholarly journals The role of drugs in the control of parasitic nematode infections: must we do without?

Parasitology ◽  
1997 ◽  
Vol 114 (7) ◽  
pp. 137-144 ◽  
Author(s):  
M. H. ROOS
Keyword(s):  
Broad Spectrum ◽  
Molecular Mechanisms ◽  
Parasite Species ◽  
Parasitic Nematode ◽  
New Drugs ◽  
Pharmaceutical Companies ◽  
Parasitic Helminths ◽  
Parasite Populations ◽  
Drug Resistant Parasite

Parasitic helminths (worms) cause serious infectious diseases in humans and domestic animals. Control of these infections relies mostly on chemotherapeutics (the anthelmintics), but resistance has developed against most of these broad-spectrum drugs in many parasite species. These resistant parasites are being used to elucidate the molecular mechanisms of drug resistance and drug action. This has led to the development of sensitive assays to detect resistant parasites, but this has not delayed the emergence of additional drug resistant parasite populations. Therefore, as development of new drugs by pharmaceutical companies is slow, we may have to be prepared for a time when broad-spectrum drugs are no longer effective, especially against worms of sheep.

Sign in / Sign up

Export Citation Format

Share Document