Marcelo Cervini

Genetic variability of 10 microsatellite markers in the characterization of Brazilian Nellore cattle (Bos indicus)

We assessed the polymorphism of 10 microsatellites in Brazilian Nellore cattle (Bos indicus) using a commercial multiplex system. Allele frequencies, polymorphism information content, heterozygosity and exclusion probability were calculated. Allele frequencies revealed that in the sample analyzed the markers were not equally polymorphic. The exclusion probabilities and the polymorphism information content of some loci in Nellore cattle were lower than in Bos taurus breeds. When all the microsatellites were considered the combined exclusion probability was 0.9989. This multiplex analysis can contribute toward pedigree information, adequate genetic improvements and breeding programs.

Genetic diversity and population structure of pumas (Puma concolor) in southeastern Brazil: implications for conservation in a human-dominated landscape

São Paulo is the most populous, developed and industrialized state of Brazil. Despite of intensive human activities, large habitat loss and fragmentation of the native vegetation cover, pumas (Puma concolor) still inhabit remnant habitat fragments in the northeastern area of the state. We investigated the occurrence of genetic structure and levels of genetic variability on pumas to aggregate basic information for conservation efforts to maintain long term viable populations of this top-predator in the region. By analyzing microsatellite loci variation, we corroborated the hypothesis of absence of genetic structure, and estimated high levels of genetic diversity (expected heterozygosity of 0.79 and mean of 10 alleles per locus). In spite of the increasing number of roadkilling and puma-human conflicts in the area, apparently pumas still maintain some level of gene flow between protected areas of the region. The observed excess of heterozygotes suggests a recent bottleneck event in this population, probably a consequence of the profound landscape transformation of the studied area during the last century; another possibility is this may be due to the observed deviation in the population sex ratio, which may be influencing the pumas’ mating system. We propose that: (1) landscape management in the study area should be focused on increasing habitat connectivity, creating protected areas and structures to allow highway crossing of pumas; (2) educational actions should be undertaken to change community perception of large carnivores, and possibly the implementation of compensatory actions to ranchers.

Conservation genetics of neotropical pollinators revisited: microsatellite analysis suggests that diploid males are rare in orchid bees.

Allozyme analyses have suggested that Neotropical orchid bee (Euglossini) pollinators are vulnerable because of putative high frequencies of diploid males, a result of loss of sex allele diversity in small hymenopteran populations with single locus complementary sex determination. Our analysis of 1010 males from 27 species of euglossine bees sampled across the Neotropics at 2–11 polymorphic microsatellite loci revealed only five diploid males at an overall frequency of 0.005 (95% CIs 0.002–0.010); errors through genetic nondetection of diploid males were likely small. In contrast to allozyme‐based studies, we detected very weak or insignificant population genetic structure, even for a pair of populations >500 km apart, possibly accounting for low diploid male frequencies. Technical flaws in previous allozyme‐based analyses have probably led to considerable overestimation of diploid male production in orchid bees. Other factors may have a more immediate impact on population persistence than the genetic load imposed by diploid males on these important Neotropical pollinators.

Genetic differentiation of urban populations of Euglossa cordata from the state of São Paulo, Brazil

Males and females of Euglossa cordata collected inside flowers of Thevetia peruviana in urban areas of eleven cities of the state of São Paulo were analysed using allozymes and nine microsatellite loci. The analyses revealed that these populations have a high genetic diversity and are under genetic equilibrium, showing low population structuring and rare diploid males; consequently, high gene flow and effective population size (Ne) are inferred. These findings corroborate previous biological observations and phylogeographic evidence that report dispersion over long distances of Euglossini species in South America.

Estimating puma Puma concolor population size in a human-disturbed landscape in Brazil, using DNA mark-recapture data

The genetics and ecology of pumas are well documented in North America but there is a lack of studies in South America, especially in Brazil. By means of a noninvasive method, faecal DNA analysis, we estimated puma abundance in two protected areas embedded in a human-disturbed landscape in the north-east of Sao Paulo state, in south-east Brazil. In 8 months of mark-recapture faeces sampling, 15 individual pumas were identified using seven microsatellite loci. The estimated abundance of pumas with the Jolly-Seber open population model was 23.81 ±SE 6.22. This is the first estimate of the abundance of pumas in a human-dominated landscape in Sao Paulo state, the most populous, developed and industrialized state of Brazil. The absence of high-quality habitats in the north- east of the state, the absence of direct competitors and the high availability of prey in protected areas are probably contributing to the high number of pumas concentrated in a relatively small area (c. 260 km 2 ). Our results will contribute to the long-term monitoring of this puma population and, combined with otherecological, behaviour- al and genetic data, will help guide conservation action to maintain a viable population of the puma in this region.

Association of CSSM066 and ILSTS011 microsatellite markers and thyroglobulin gene SNP with backfat in Canchim cattle

Canchim, a synthetic breed of cattle derived from the Charolais and Zebu group has been used in the beef-cattle industry in Brazil as an alternative for intensifying production. One of the main concerns with this breed is its poor fat deposition and consequently, there is an effort to increase the performance for this trait. The thyroglobulin gene is located in a QTL region for fat deposition, and reports describe the influence of a polymorphism in the 5´ leader sequence of that gene on marbling and subcutaneous fat thickness. This study analyzed the association of this polymorphism in the thyroglobulin gene, as well as of two flanking microsatellite markers, CSSM066 and ILSTS011, with backfat thickness in 987 Canchim beef cattle. The CSSM066 and ILSTS011 microsatellite markers have a effect on fat thickness in the studied populations. However, this trait did not have association with the polymorphism of the thyroglobulin gene, which suggests that other genes of bovine chromosome 14 may be responsible for the variation in this trait.