RESUMEN

B chromosomes in Prochilodus lineatus, a migratory neotropical fish, were analyzed in a comparative study among populations from the Dourada lagoon (State of Paraná, Brazil) and from Mogi-Guaçu river (State of São Paulo, Brazil). The data on C-banding and fluorescent in situ hybridization with a satellite DNA probe (SATH1), indicate that the small metacentric B chromosome might correspond to an isochromosome. On the other hand, both populations presented a distinct set of B chromosomes, differentiated either by their number and by the presence of variant B types in the population from Mogi-Guaçu river. The present results indicate that the B chromosomes of P. lineatus should have an ancient origin, and have undergone a differential evolutionary pathway among distinct populations.

Asunto(s)

Pintura Cromosómica , Cromosomas , Cipriniformes/genética , Evolución Molecular , Cariotipificación , Animales , Centrómero , Mapeo Cromosómico , Pintura Cromosómica/métodos , ADN Satélite/análisis , Femenino , Frecuencia de los Genes , Heterocromatina , Hibridación Fluorescente in Situ , Isocromosomas/fisiología , Masculino , Metafase , Región Organizadora del Nucléolo/metabolismo , Ploidias , Tinción con Nitrato de Plata