oceany: Hybrid speciation

Evidence: 64 • authority: 72

Reinforcement is a process of speciation where natural selection increases the reproductive isolation (further divided to pre-zygotic isolation and post-zygotic isolation) between two populations of species. This occurs as a result of selection acting against the production of hybrid individuals of low fitness. The idea was originally developed by Alfred Russel Wallace and is sometimes referred to as the Wallace effect. The modern concept of reinforcement originates from Theodosius Dobzhansky. He envisioned a species separated allopatrically, where during secondary contact the two populations mate, producing hybrids with lower fitness. Natural selection results from the hybrid's inability t…

Evidence: 57 • authority: 92

Evidence: 57 • authority: 92

Hybrid fertility and the rarity of homoploid hybrid speciation.. Hybrid speciation is increasingly being recognized as an important driver in diversification. Of the two forms of hybrid speciation, polyploid hybrid speciation is considered more common as it provides instant reproductive isolation either completely or partially, due to meiotic incompatibilities with the parental species. Homoploid hybrid speciation is considered rare, as it lacks the instant reproductive isolation conferred by polyploidy, though there are an increasing number of examples in the literature. Reproductive isolation in the nascent homoploid hybrid species is commonly achieved by niche divergence, often into terr…

Evidence: 51 • authority: 72

In parapatric speciation, two subpopulations of a species evolve reproductive isolation from one another while continuing to exchange genes. This mode of speciation has three distinguishing characteristics: 1) mating occurs non-randomly, 2) gene flow occurs unequally, and 3) populations exist in either continuous or discontinuous geographic ranges. This distribution pattern may be the result of unequal dispersal, incomplete geographical barriers, or divergent expressions of behavior, among other things. Parapatric speciation predicts that hybrid zones will often exist at the junction between the two populations. In biogeography, the terms parapatric and parapatry are often used to describe…

Evidence: 44 • authority: 92

Phylogeographic Breaks With and Without Contemporary Barriers to Migration in the Lizard Acanthodactylus erythrurus.. Identifying phylogeographic breaks and deciphering the relative contributions of environmental extrinsic (e.g., geological barriers, ecological gradients) and organismal intrinsic (e.g., limited dispersal, reproductive incompatibilities) factors to their persistence remain challenging, especially in the absence of genomic data. Here, we address this issue using parapatric lineages of the lizard Acanthodactylus erythrurus in south-western Morocco. A previous study based on nine nuclear loci identified two phylogeographic units (coastal vs. inland) whose separation did not ali…

Evidence: 44 • authority: 92

Digest: Incipient hybrid speciation in the Black-cheeked Gnateater?. Homoploid hybrid speciation continues to be debated, particularly regarding the role of hybridization in generating reproductive isolation. Lima et al. (2026) present genetic evidence for an admixed lineage in the Black-cheeked Gnateater (Conopophaga melanops). Notably, patterns of isolation by distance, clinal plumage variation, and discordant signals in mitochondrial and nuclear markers complicate this interpretation. These findings highlight the difficulty of distinguishing hybrid speciation from secondary gene flow and underscore the reticulated nature of evolution.. Authors: Ottenburghs J.. Journal: Evolution; interna…

Evidence: 44 • authority: 72

Allopatric speciation is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Its name comes from Ancient Greek ἄλλος (állos) 'other' and πατρίς (patrís) 'fatherland', and is also called geographic speciation, vicariant speciation, and its earlier name the dumbbell model. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, re…

Evidence: 44 • authority: 80

Evidence: 44 • authority: 88

Evidence: 44 • authority: 92

Evidence: 44 • authority: 72

Evidence: 44 • authority: 72