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At least 127 records · Page 7Linked to original sources
PubMed2001

Perspective: reverse evolution.

For some time, the reversibility of evolution was primarily discussed in terms of comparative patterns. Only recently has this problem been studied using experimental evolution over shorter evolutionary time frames. This has raised questions of definition, experimental procedure, and the hypotheses being tested. Experimental evolution has provided evidence for multiple population genetic mechanisms in reverse evolution, including pleiotropy and mutation accumulation. It has also pointed to genetic factors that might prevent reverse evolution, such as a lack of genetic variability, epistasis, and differential genotype-by-environment interactions. The main focus of this perspective is on laboratory studies and their relevance to the genetics of reverse evolution. We discuss reverse evolution experiments with Drosophila, bacterial, and viral populations. Field studies of the reverse evolution of melanism in the peppered moth are also reviewed.

Animals↗
PubMed2025

Adaptation of the Cyst Nematode Globodera pallida to the Colinear Potato Resistant QTLs GpaVvrn and GpaVspl Involved Distinct Genomic Regions and Absence of Cross-Virulence.

The use of alternative methods to control cyst nematode populations has accelerated since the ban of chemical nematicides in Europe. The resistant QTL GpaVvrn, derived from the wild species Solanum vernei, is widely present in resistant European potato cultivars and provides strong protection against Globodera pallida populations although a risk of resistance breakdown has already been demonstrated in both experimental evolution studies and field populations. The wild relative S. sparsipilum, harbouring the resistant QTL GpaVspl, would be an interesting alternative source of resistance to control virulent G. pallida. The goal of the present study was to understand the genomics of adaptation of the nematode to these two colinear resistant QTLs. Starting with two natural populations, an experimental evolution approach allowed, after 10 generations on resistant potato genotypes, selecting independent nematode lineages adapted to each QTL. These virulent lineages were analysed through a combination of phenotyping and genome scans approaches. Phenotyping enabled the quantification of virulence levels and confirmed resistance breakdowns. Pool-Seq whole genome sequencing followed by genome scan analyses identified genomic regions under selection, potentially involved in the adaptive mechanisms to each resistance factor. Candidate genes within these regions provided insights into the genetic basis of adaptation, revealing effectors known to suppress plant immunity. As genome scans highlighted distinct genomic regions for the adaptation to both resistant factors, we were able to predict and phenotypically confirm the absence of cross-virulence between nematode lineages evolving on GpaVvrn and GpaVspl. These findings have significant implications for the design of effective and sustainable resistance management strategies.

Animals↗
PubMed1987

Codification and evolution of experimentally observed specific recognition sites for restriction enzymes on DNA.

The list of published restriction endonucleases along with their substrates provides an excellent data base for the evaluation of the evolution and codification of the key elements for specific recognition sites on the DNA. In this paper the considerations will be limited to palindromic tetramer-, pentamer-, and hexamer-sequences. It is basically assumed that each base pair within these sequences has to be recognized by directionally unique bidentate hydrogen bonds either within the plane of the base pair or by bridging the appropriate H-bond donor/acceptor groups of the neighbouring bases of the same strand. Thus sequence specificity is mediated by twelve (eight) H-bonds, originating from the protein recognition modules. Besides a pronounced preference for GC base pairs expressed by their high frequency in the most abundant sequences, serving the need of maximal thermodynamic stability of the double helical substrates, it can also be shown that the stacking of consecutive bases within the recognition site sequences plays a major role in shaping the particular DNA/protein interface. Finally it will be demonstrated that the full set of sequences discussed in this paper can readily be derived by stepwise expanding the vocabulary of three simple tetrameric sequences by inserting single base pairs into the centre of a minimal sequence, thus creating all the published pentameric restriction sites, or by inserting/adding two GC base pairs in a palindromic way, thus creating the known multiplicity of hexameric sites.

Base Sequence↗