Several phylogeographic studies of seabirds have documented low genetic diversity that has been attributed to bottleneck events or individual capacity for dispersal. Few studies have been done in seabirds on the Brazilian coast and all have shown low genetic differentiation on a wide geographic scale. The Kelp Gull is a common species with a wide distribution in the Southern Hemisphere. In this study, we used mitochondrial and nuclear markers to examine the genetic variability of Kelp Gull populations on the Brazilian coast and compared this variability with that of sub-Antarctic island populations of this species. Kelp Gulls showed extremely low genetic variability for mitochondrial markers (cytb and ATPase) and high diversity for a nuclear locus (intron 7 of the β-fibrinogen). The intraspecific evolutionary history of Kelp Gulls showed that the variability found in intron 7 of the β-fibrinogen gene was compatible with the variability expected under neutral evolution but suggested an increase in population size during the last 10,000 years. However, none of the markers revealed evidence of a bottleneck population. These findings indicate that the recent origin of Kelp Gulls is the main explanation for their nuclear diversity, although selective pressure on the mtDNA of this species cannot be discarded.

Museum collections have been widely used as sources of biological samples for molecular biology studies and there are several methodologies and techniques to obtain and analyze DNA from tissues archived in museums, but most of these protocols have been developed for a specific tissue or are commercial kits. We present a simple protocol for extracting and amplifying DNA segments from sloth museum specimens. With this simple protocol we analyzed DNA fragments from 64% of 64 skin samples from three-toed sloths (Bradypus variegatus and Bradypus tridactylus) archived in three different museums: 43 samples from the University of São Paulo Museum of Zoology (Museu de Zoologia da Universidade de São Paulo, MUZUSP) São Paulo, São Paulo, Brazil; 18 samples from the Emílio Goeldi Museum (Museu Paraense Emílio Goeldi, MPEG), Belém, Pará, Brazil; and 3 samples from the Museum of Vertebrate Zoology (MVZ) University of California, Berkeley, USA. The specimens sampled ranged in age from 18 to 108 years old. Our methodology allowed the recovery of up to 700 bp of mitochondrial DNA and 400 bp of nuclear genes. Thereafter, it is useful for genetic diversity studies of three-toed sloths and could be applied to other animals.

The bat species Platyrrhinus lineatus and P. recifinus (Phyllostomidae: Stenodermatinae) are ecologically important because of their capacity for seed dispersal. P. recifinus is endemic to the Atlantic rain forest and is considered vulnerable by the IUCN. The lack of distinct morphological features makes identification of the two species a difficult task. This study was aimed at testing the hypothesis that these are actually two distinct species by using PCR-RFLP of the mitochondrial cytocrome b gene. The results showed no shared haplotypes, demonstrating that these are, in fact, two distinct species. No polymorphism was obtained for P. recifinus, which could be a sign of low genetic diversity in this threatened species.

Two sibling species of Biomphalaria, B. tenagophila and B. occidentalis were identified using isozyme patterns obtained by horizontal gel electrophoresis. Six diagnostic enzymatic loci were identified in digestive gland homogenates. The results enable us to distinguish the species, calculate the Nei's coefficient of genetic similarity, and provide a basis for making inferences about the pattern of these two planorbid species colonization and distribution.