Abstract
Hybridization between distinct species of animals and subsequent genetic introgression plays a considerable role in the speciation process and the emergence of adaptive characters. Fitness of between-species hybrids usually sharply decreases with the divergence time of the concerned species and the divergence depth, which still allows for a successful crossing differs among principal clades of vertebrates. Recently, a review of hybridization events among distinct lizard species revealed that lizards belong to vertebrates with a highly developed ability to hybridize. In spite of this, reliable reports of experimental hybridizations between genetically fairly divergent species are only exceptional. Here, we show the results of the crossing of two distinct allopatric species of eyelid geckos possessing temperature sex determination and lacking sex chromosomes: Eublepharis macularius distributed in Pakistan/Afghanistan area and E. angramainyu, which inhabits Mesopotamia and adjacent areas. We demonstrated that F1 hybrids were viable and fertile, and the introgression of E. angramainyu genes into the E. macularius genome can be enabled via a backcrossing. The examined hybrids (except those of the F2 generation) displayed neither malformations nor a reduced survival. Analyses of morphometric and coloration traits confirmed phenotypic distinctness of both parental species and their F1 hybrids. These findings contrast with long-term geographic and an evolutionary separation of the studied species. Thus, the occurrence of fertile hybrids of comparably divergent species, such as E. angramainyu and E. macularius, may also be expected in other taxa of squamates. This would violate the current estimates of species diversity in lizards.
Highlights
The fact that related species of animals are sometimes able to hybridize is known since the beginning of evolutionary biology [1]
We studied the following nine categories of the parental species and their hybrids that are further referred to as follows (the abbreviations are given in parentheses; on the first place there is always an abbreviation for a female, cross (x) with a male on the second position; the number and the sexes of these specimens in Table 1): 1. PM−the parental generation of the E. macularius, both parents belong to the E. macularius (M); 2
The breeding male of the E. angramainyu was successively paired with 17 virgin females of the E. macularius. 15 of these females subsequently produced eggs
Summary
The fact that related species of animals are sometimes able to hybridize is known since the beginning of evolutionary biology [1]. Presence of hybrid zones and/or introgressed genes has been documented in many animal taxa (e.g., fruit flies: [7]; butterflies: [8]; fishes: [9]; toads: [10]; snakes: [11]; lizards: [12]; Darwin’s finches: [13]; nightingales: [14]; house mice: [15]; dolphins: [16]) This suggests that at least in the terminal branches of the phylogenetic tree, a predominantly divergent pattern of evolution caused by cladogenesis may be supplemented by a complementary process (syngenesis). E.g., some of the Darwin’s finches, interspecific hybrids exhibit elevated fitness when compared with the parental species and genetic identities of the species have become fuzzy [25]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
