Variação genética em Tayassu pecari (Link, 1795) e em Pecari tajacu (Linnaeus, 1758). Uma contribuição para a conservação dessas espécies

Abstract

The tayassuidae family, order Artiodactyla, occurs exclusevely in the American continet and has three extant species: Tayassu pecari, the White-lipped peccary, Pecari tajacu, the collared peccary, Catagonus wagneri, the chacoan peccary. The existence of a fourth species in the family, Pecari maximus, recently discovered, is being discussed. White-lipped peccaries occur from southern Mexico through northern Argentina, while collared peccaries have a wider distribution: from southern United States through northern Argentina. Both species play key roles in the ecossystem, being part of the trophic chain and acting as seeds predators and dispersers. They are hunted in various levels throughout thier range and suffer with habitat changes provoked by humans.Microssatellites are short repetitive sequences of DNA found all over the genome and present a high degree of polimorphysm, codominance and are selective neutral, therefore being considered a ideal molecular marker for populational studies. The flanking regions of these microssatellites tend to be conserved among related species, wich makes possible the cross amplification.The aim of this work was to describe and charaterize microssatellite loci for Tayassu pecari and to test their aplicability to population studies of Pecari tajacu. A partial enriched genomic library was constructed through the DNA cleavage with restriction enzymes, hybridiztion of the fragments with repetitive biotinilated probes and magnetic recovery of hybrids with streptavidincoated magnetic beads. Among 192 recombinant clones that were sequenced, 60 repetitive regions were obtained. Design of primers was possible for 19 of them and they were tested in 30 individuals from a wild population of White-lipped and 23 from a captive population of collared peccaries. 13 loci amplified in the White-lipped peccary population and ten of them polimorphyc. The genetic diversity in this population was considered moderated, two loci deviated from Hardy-Weinberg Equilibrium in response to the presence of an homozygous excess caused by null alleles. The genetic diversity found in the collared peccary population was slightly higher, probably due to the mixed origin of the animals. This difference may also be a result of different patterns or reproduction in the two species: while White-lipped herd seem to function as a relatevely closed reproductive units, the social flexibility of collared peccaries that occurs in the wild may favour the genetic diversity in the species, so when a captive population is established, its genetic diversity, as a reflex of the total genetic diversity, is also higher. There were more related individuals in the White-lipped population than were found for the collared population, which might be a consequence of the reproductive patterns of the two species. The genetic markers described here can be used in for popualtion studies in both species, and may base future managment and conservation programs for the maintaince of the peccaries.