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La filogenética y la geografía integrales revelan la diversificación cuaternaria y la discordancia mitocondrial-nuclear en Odorrana schmackeri sensu lato (Anura, Ranidae): las funciones de la elevación Qinghai-tibetana, las oscilaciones climáticas y el flujo de genes asimétricos
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Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.
The genetics of speciation involves the different traits or isolating mechanisms preventing gene exchange, leading to reproductive isolation. Reproductive isolation can be due to reproductive barriers that have effects either before or after the formation of a zygote. Pre-zygotic mechanisms prevent fertilization from occurring, and post-zygotic...
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Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
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Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.
This phenomenon plays a significant evolutionary role in all organisms, and depending on the rates of gene flow, the mechanism either induces genetic diversity or generates genetic homogeneity among populations. When the rate of gene flow is low, the introduction of new alleles into a population generates genetic diversity. On the other hand, a high rate of...
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Overview
Speciation usually occurs over a long evolutionary time scale, during which the species may be isolated or continue to interact. If two emerging species start to interbreed, reproductive barriers may be weak, and gene flow can occur again. At this point, the selection of hybrids across the two populations may either stabilize the newly mixed group into a single population or reinforce the distinction between them as new species. Speciation may occur gradually or rapidly, and in some...
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Hybrid zones are narrow regions where two closely related species interact, mate, and produce hybrids. Relative to either parent species, hybrids may possess distinct phenotypic or genetic differences that impact their survival and reproductive success. The genetic variances introduced by hybridization influence species diversity and speciation processes within the hybrid zone.
Gene flow and natural selection are evolutionary mechanisms that shape the outcome of a hybrid zone. Gene flow...
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Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while...