Molecular phylogeny and biogeography of the Cuban genus Girardinus Poey, 1854 and relationships within the tribe Girardinini (Actinopterygii, Poeciliidae).

Phylogenetic relationships among members of the freshwater fish tribe Girardinini were inferred to test existing colonization and diversification hypotheses for this group in the Caribbean. The genetic material examined was mitochondrial (cytochrome b, 1140 bp) and nuclear (RAG-1 and beta-actin, 2450 bp) DNA from 161 specimens representing 44 ingroup and three outgroup taxa. Our mtDNA and combined data matrix (mtDNA+nuclear DNA) results rendered a well-supported phylogeny for the tribe Girardinini and suggest the need to review the group's current taxonomy. From the data presented here, it may be inferred that the Girardinini diverged from other poeciliid fishes approximately 62 Mya ago in the Palaeocene period. This estimate, however, conflicts with the hypothesis that today's vertebrate fauna is the result of the more recent colonization of the Antillean islands during the Early Oligocene (35-33 Mya ago). The isolation of western, central and eastern Cuba during the Miocene and that of the Juventud Island and Guanahacabibes Peninsula during the Pliocene, are the main geologic events that could have promoted speciation in this group.

Amplificación al azar del ADN de 5 poblaciones cubanas de peces larvívoros del género Rivulus

Se amplificó al azar el ADN de 10 individuos de 5 poblaciones de Rivulus colectados en la región occidental de Cuba. De la amplificación, empleando 5 cebadores, no resultó ningún marcador monomórfico, lo que evidenció una alta variabilidad genética entre los peces de las 5 poblaciones. Según la distancia genética entre los individuos, se forman 4 grupos, para cada uno de los cuales aparecen marcadores genéticos de RAPD (ADN polimórfico amplificado al azar) que son específicos, porque no se evidencian en el resto de los individuos. Estos resultados apoyan la utilización del RAPD como una herramienta eficiente para la caracterización genética de peces cubanos del género Rivulus.

DNA from 10 individuals from 5 populations of Rivulus collected in the western region of Cuba was amplified at random. No monomorphic marker resulted from the amplification by using 5 primers, which showed the high genetic variability existing among the fishes of the 5 populations. According to the genetic distance among the individuals, they were divided into 4 groups, for which there are specific genetic markers of RAPD, since they are not observed in the rest of the subjects. These results support the use of RAPD as an efficient tool for the genetic characterization of Cuban fishes of the Rivulus genus.

[Amplification at random of the DNA from 5 Cuban populations of larviphage fishes of the Rivulus genus]. / Amplificación al azar del ADN de 5 poblaciones cubanas de peces larvívoros del género Rivulus.

DNA from 10 individuals from 5 populations of Rivulus collected in the western region of Cuba was amplified at random. No monomorphic marker resulted from the amplification by using 5 primers, which showed the high genetic variability existing among the fishes of the 5 populations. According to the genetic distance among the individuals, they were divided into 4 groups, for which there are specific genetic markers of RAPD, since they are not observed in the rest of the subjects. These results support the use of RAPD as an efficient tool for the genetic characterization of Cuban fishes of the Rivulus genus.