Sentence examples for speciation either from inspiring English sources

Eventually, divergent selection can lead to complete reproductive isolation (i.e. ecological speciation), either as a by-product of divergent selection (via linkage disequilibrium [6]), or directly when the genes involved in reproductive isolation are under ecologically-based divergent selection (via pleiotropy [2]).

These cycles could have resulted in speciation, either through physical isolation (allopatric speciation) or changes in habitat (sympatric or ecological speciation).

Because genetic divergence accompanied by morphological similarity is not uncommon, cryptic speciation either remains overlooked [ 28, 46] or species diagnoses focus exclusively on molecular markers [ 47].

These cycles could influence speciation either through genetic differentiation spurred by range fragmentation into glacial refugia or through admixture or introgression as previously isolated entities mixed and created new and differing gene pools which contributed to speciation [ 33].

In all of these studies Pb and Zn concentrations and speciation are either measured or calculated for very restricted fluid compositions in terms of, pH, and other solute activities.

Figure  1 also illustrates the two main adaptive routes to speciation, where either ecological differentiation or reproductive isolation is directly driven by disruptive selection.

We infer that this scattered phylogenetic distribution of selfing is best described by models including up to eight independent outcrossing-to-selfing transitions and very low rates of speciation (and either moderate or zero rates of extinction) associated with selfing.

There are at least two ways that specialization can promote speciation rates: either by a genetic linking between resource use and mate choice, which could create "host races" with an increasing genetic differentiation [ 10, 13- 15], or because a resource specialist's host will tend to be more patchily distributed and thus increase the likelihood of differentiation among populations [ 11, 16].

However, speciation is either not really adaptive (since it relies on abrupt changes of the environment or on mutation accumulation) or it requires the simultaneous action of multiple sources of selection (diversifying selection on female preferences combined with diversifying selection on male ornaments).

By studying patterns of introgression in hybrid zones, candidate genomic regions that are either speciation genes, or linked to speciation genes, can be identified on the basis of reduced levels of introgression, whereas candidate genomic regions that are either beneficial genes, or linked to beneficial genes, can be detected from increased levels of introgression [ 4- 6, 11, 15, 28].

Finally, we find no signature of episodic molecular evolution related to either speciation events or the K-Pg boundary that could systematically mislead inferences from genetic data.