Repeated and independent adaptation to specific environmental conditions from standing genetic variation is common. However, if genetic variation is limited, the evolution of similar locally adapted traits may be restricted to genetically different and potentially less optimal solutions, or prevented from happening altogether. Using a quantitative trait locus (QTL) mapping approach, we identified the genomic regions responsible for the repeated pelvic reduction (PR) in three crosses between nine-spined...
Tue Aug 11, 2020 03:00
CD44 is a membrane-bound extracellular matrix (ECM) receptor interacting, among others, with hyaluronic acid (HA) and osteopontin (OPN). Cancer progression and metastasis are greatly influenced by the cancer micro-environment, consisting of ECM, immune cells and cancer-associated fibroblasts (CAF). Recruitment of fibroblasts (FB) into the role as CAFs is caused by paracrine signals from the tumor, including TGFb1, PDGF and OPN. The effect of OPN on the transformation of FB into CAF is mediated by...
Tue Aug 11, 2020 03:00
Premise of the study: The family Salicaceae has proved taxonomically challenging, especially in the genus Salix, which is speciose and features frequent hybridization and polyploidy. Past efforts to reconstruct the phylogeny with molecular barcodes have failed to resolve the species relationships of many sections of the genus. Methods: We used the wealth of sequence data in the family to design sequence capture probes to target regions of 300-1200 base pairs of exonic regions of 972 genes. Results:...
Tue Aug 11, 2020 03:00
Many bacterial species that cannot sporulate, such as the model bacterium Escherichia coli, can nevertheless survive for years under resource exhaustion, in a state termed long-term stationary phase (LTSP). Here we describe the dynamics of E. coli adaptation during the first three years spent under LTSP. We show that during this time E. coli continuously adapts genetically, through the accumulation of mutations. For non-mutator clones, the majority of mutations accumulated appear to be adaptive under...
Tue Aug 11, 2020 03:00
mtDNA-based phylogenetic trees of the order Primates were constructed by the minimum evolution (ME) and maximum likelihood (ML) methods. Branch lengths were compared with the mean female age at first birth in the taxa studied. Higher reproductive age in females triggers a lower number of generations through time and, on average, at the molecular level smaller evolutionary distances between related taxa. However, this relationship is significant when the phylogeny is resolved by the ME method rather...
Tue Aug 11, 2020 03:00
It is generally accepted that the absence of recombination reduces the efficacy of natural selection for, or against, mutations. A special case is Mullers Ratchet (MR) whereby non-recombining genomes experience irreversible fitness decline due to the accumulation of deleterious mutations. MR has been a main hypothesis for sexual reproduction as well as many other biological phenomena. We now ask whether the fitness decline can indeed be stopped if an asexual population turns sexual to become recombining....
Tue Aug 11, 2020 03:00
Species are often defined by their ability to interbreed (i.e., Biological Species Concept), but determining how and why reproductive isolation arises between new species can be challenging. In the Mimulus tilingii species complex, three species (M. caespitosa, M. minor, and M. tilingii) are largely allopatric and grow exclusively at high elevations (>2000m). The extent to which geographic separation has shaped patterns of divergence among the species is not well understood. In this study, we...
Tue Aug 11, 2020 03:00
Identifying age-dependent trade-offs between reproductive effort and survival in wild organisms is central for understanding the evolutionary mechanisms of senescence. According to the disposable soma theory, early-life energy investments in reproduction compromise late-life investments in somatic maintenance - leading to senescence. Once thought to only be detectable in captive populations, senescence has recently been documented by several longitudinal studies of wild organisms. However, some reproductive...
Tue Aug 11, 2020 03:00
Anticipating the genetic and phenotypic changes induced by natural or artificial selection requires reliable estimates of trait evolvabilities (genetic variances and covariances). However, whether or not multivariate quantitative genetics models are able to predict precisely the evolution of traits of interest, especially fitness-related, life-history traits, remains an open empirical question. Here, we assessed to what extent the response to bivariate artificial selection on both body size and maturity...
Mon Aug 10, 2020 03:00
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου