Evidencias moleculares de hibridación entre Serinus canaria domestica (L., 1758) y Spinus barbatus (Molina, 1782) (Aves: Fringillidae)

ResumenEn este estudio se muestran evidencias moleculares de éxito en la hibridación entre Serinus canaria domestica (linnaeus, 1758) y Spinus barbatus (molina, 1782). Como parte de unasecuencia de retrocruzamiento, se logró reproducir híbridos F2 a partir de hembras híbridasfértiles viables F1 x S. c. domestica. La F1 fue la descendencia entre P0= Serinus c. domestica x Spinus barbatus. Las secuencias de nucleótidos de dos segmentos de ADN, citocromo b mitocondrial (Cyt b) y el receptor de tirosina quinasa muscular (MuSK) del ADN nuclear se obtuvieronde tres especímenes híbridos F2. Tanto las secuencias de Cyt b como de MuSK señalaron fuertesoporte filogenético a la condición genética híbrida de los tres embriones F2. De esta manera laevidencia molecular refleja el éxito en el cruce interespecífico entre S. barbatus con S. c. domestica y que es posible obtener híbridos fértiles viables F1 (en este caso hembras) y F2 entre estosdos linajes en poblaciones naturales.AbstractIn this study we show molecular evidences of success in hybridization between Serinuscanaria domestica and Spinus barbatus. As part of a sequence of backcrossing we have achieved toreproduce F2 hybrids of fertile hybrid females F1 with parental S. c. domestica. F1 was the offspring between, P0= S. c. domestica x S. barbatus. In this study the space where the observationsand the breeding success are carried out between these species, they are described: is a roomwith the following measures; 4,45 m (lenghty) x 1,60 m (width) x 2,30 m (high), located in anurban building; specifically, glassed-balcony at a height of 10,60 m above ground level, facing someornamental and exuberant canopy trees of Platanus orientalis (L., 1753) and with direct entranceof natural sunlight, in urban city of Santiago, Chile, where his perceptual world develops. Wetook care to keep the biotic and abiotic factors under control; specifically, incoming natural light,ambient vegetation and temperature. On the other hand, we fed the individuals appropriatelyand provided them with plenty of clean water to drink and get clean, where there were no predators. In sum, the individuals were kept in a healthy environment. The backcrossing between themale S. c. domestica (generation 0) bred with two viable hybrid F1 offspring females, it gave as resulted in a total of three independent generations of F2 hybrids (n = 12). All the individuals cameout healthy, and none of them died, despite being inbred lineages. Three embryos representativeof the F2 hybrids were sacrificed and deposited in 99% alcohol. Nucleotide sequences of twoDNA segments, mitochondrial cytochrome b (Cyt b) and muscle-specific receptor tyrosinekinase (MuSK) gene of the nuclear DNA were obtained from three F2 hybrid specimens. Themodel of molecular evolution with the greatest adjustment to the data obtained by jModeltestwas GTR + I + G (I = 0,1450, G = 0,0930), according to the phylogenetic analysis of mitochondrial DNA (Fig. 1a), the female progenitor P0 is S.c.domestica. This conclusion is based on the evi-dence that mitochondrial DNA in birds, as well as in most animal groups, is exclusively inheritedthrough the maternal ways. The same analysis carried out with the nuclear MuSK gene showsthat the parental male P0 of the embryos analyzed is very much related to S. barbatus (Fig. 1b).The Cyt b and MuSK region show strongly support to hybrids genetic condition of the three F2embryos. Intergeneric hybrids are usually sterile, but it is worth noting that genera of Fringillidaeare very closely related (the Family as a whole is only 12 million years old, and most genera inthe terminal canary-siskin group are <5 million years old). This is simply a case of poor classification with oversplitting or maybe the nature of these lineages are fractals, since in most of thePasseriformes, family-level taxa are more than 20 million years old, and in other groups of Avesfamilies and genera are even older. Then hybridization takes place more easily in captivity. Manyauthors considered that hybridization in birds is not important because hybrids are formed inproportion 1/50,000 specimens. Despite this, many bird hybrids have been created in captivity.In addition, hybrids produced ex situ under controlled conditions would play an importantrole for reproductive success and subsequent interspecific viability. The main conclusions derived from this study are as follows:1) The present report strongly indicates that hybridizations have occurred among S. c.canary x S. barbatus. 2) In this way the molecular evidence reflects and justifies the successin interspecific reproduction between S. barbatus with S. c. domestica and that it is possible toobtain viable fertile hybrids F1 (in this case females) and F2 between these two lineages, 3) Andconsequently the close genetic affinity between these two genera and the formation of hybridsin natural populations should not discard.