Abstract Cancer is a genetic disease present in all complex multicellular lineages. Finding ways to eliminate it is a goal of a large part of the scientific community and nature itself. Early, scientists realized that the cancer incidence at the species level was not related to the number of cells or lifespan, a phenomenon called Peto's Paradox. The interest in resolving this paradox triggered a growing interest in investigating the natural strategies for cancer suppression hidden in the animal's genomes. Here, we gathered information on the main mechanisms that confer resistance to cancer, currently described for lineages that have representatives with extended longevity and large body sizes. Some mechanisms to reduce or evade cancer are common and shared between lineages, while others are species-specific. The diversity of paths that evolution followed to face the cancer challenge involving coding, regulatory, and structural aspects of genomes is astonishing and much yet lacks discovery. Multidisciplinary studies involving oncology, ecology, and evolutionary biology and focusing on nonmodel species can greatly expand the frontiers of knowledge about cancer resistance in animals and may guide new promising treatments and prevention that might apply to humans.

Resumo A recente revolução nos métodos de sequenciamento vem permitindo a geração de dados moleculares em larga escala em velocidades e custo-benefício nunca sonhados 15 anos atrás. Esses bancos de dados massivos podem ser usados para compreender processos biológicos complexos, sendo empregados atualmente para inúmeros grupos taxonômicos. A transição de diversas áreas da Ciência como Ecologia, Sistemática, Biologia do Desenvolvimento e Biologia da Conservação para a Era Genômica carrega a promessa de alavancar nossa compreensão acerca da biodiversidade funcional e estrutural de mamíferos neotropicais, a medida que as novas tecnologias de seqüenciamento transformam praticamente qualquer espécie em um novo modelo de estudo. Nessa revisão, fornecemos uma visão geral sobre o desenvolvimento recente de tecnologias genômicas. Em seguida, ilustramos como essas tecnologias estão sendo usadas para estudar mamíferos neotropicais em diferentes campos de estudo. Por fim, discutimos advertências e perspectivas futuras, com o aumento da disponibilidade de seqüências genômicas abrindo novos caminhos para a pesquisa científica. Embora progredindo em um ritmo mais lento quando comparado a outros mamíferos do mundo, o estudo genômico de mamíferos Neotropicais têm fornecido informações essenciais sobre nossa fauna endêmica e promete entregar muito mais nos próximos anos. Considerando a grande importância do reino neotropical e os diferentes tipos de ameaças à biodiversidade dessa área biogeográfica, o futuro da diversidade de mamíferos neotropicais depende, em grande parte, de ações de conservação urgentes baseadas no conhecimento científico, tornando os métodos genômicos mais úteis do que nunca.

Abstract The recent revolution in sequencing methods allowed the generation of genomic, transcriptomic, and other large-scale data at a speed and low cost undreamed fifteen years ago. These large datasets can be used for understanding complex processes and are already a reality for many taxonomic groups in the world. The transition of several biological fields such as ecology, systematics, developmental biology and biological conservation into the genomic era promises to foster our understanding of functional and structural mammalian biodiversity in Neotropics, as new sequencing technologies liberate virtually any species from genomic ignorance and transform them into new study models. Here, we aim to first give a brief overview on recent development of genomic technologies and then illustrate how these technologies are being used to study Neotropical mammals in several fields. Finally, we discuss caveats and future perspectives, as the number of genomic sequences available is continually increasing and opening new avenues for research. Although progressing in a slower pace when compared to other mammals of the world, genomics has already provided important insights and promises to deliver many more. Considering the great importance of Neotropical realm and all the threats that biodiversity must face on this biogeographical area, the future of the diversity of mammals here depends largely on urgent conservation actions based on scientific knowledge, making genomics as useful as never before.

Developmental processes and their results, morphological characters, are inherited through transmission of genes regulating development. While there is ample evidence that cis-regulatory elements tend to be modular, with sequence segments dedicated to different roles, the situation for proteins is less clear, being particularly complex for transcription factors with multiple functions. Some motifs mediating protein-protein interactions may be exclusive to particular developmental roles, but it is also possible that motifs are mostly shared among different processes. Here we focus on HoxA13, a protein essential for limb development. We asked whether the HoxA13 amino acid sequence evolved similarly in three limbless clades: Gymnophiona, Amphisbaenia and Serpentes. We explored variation in ω (dN/dS) using a maximum-likelihood framework and HoxA13 sequences from 47 species. Comparisons of evolutionary models provided low ω global values and no evidence that HoxA13 experienced relaxed selection in limbless clades. Branch-site models failed to detect evidence for positive selection acting on any site along branches of Amphisbaena and Gymnophiona, while three sites were identified in Serpentes. Examination of alignments did not reveal consistent sequence differences between limbed and limbless species. We conclude that HoxA13 has no modules exclusive to limb development, which may be explained by its involvement in multiple developmental processes.

Differences in distribution, prey species, season and social learning opportunities influence the feeding tactics used by marine mammals. Here, we analyze the coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Van Bénéden, 1864, Delphinidae) and its relation to seasonality and the presence of calves. In a total of 201 feeding bouts, we observed four types of coordinated feeding tactics, which differed in frequency and in mean number of engaged individuals. Tactics in which dolphins used their bodies to herd and capture prey were the most frequent, presenting a higher frequency and engaging a higher number of individuals, suggesting that these tactics are better for capturing fishes which form larger schools. Furthermore, the seasons influenced the feeding behavior used by dolphins. During spring-summer, a longer duration of bouts and a larger number of individuals engaged in the feeding tactics was observed, which may be related to the seasonal spawning of larger schooling fish, such as Sardinella brasiliensis (Steindachner, 1879). Calves were present in 95% of all coordinated feeding tactic occurrences. This study indicates a complete preference of dolphins for coordinating their actions to capture prey and for the first time reports the presence of calves in the coordinated tactics and jumps. This broadens the current knowledge of the Guiana dolphin feeding tactics.

Indivíduos da população dos golfinhos estuarinos, Sotalia guianensis (Van Bénéden, 1864), da Baía de Sepetiba (22º35'S, 44º03'W) Estado do Rio de Janeiro, sudeste do Brasil, foram catalogados pelo método de foto-identificação durante o período de fevereiro de 1994 a julho de 2006. Foram conduzidas 72 expedições de barco, resultando na identificação e catalogação de 217 botos. Destes 79 (36,4%) foram recapturados pelo menos uma vez durante o período de estudo; o intervalo médio entre as recapturas foi de 40,6 ± 31,1 meses. A presença de pares de mães-filhotes foi numerosa ao longo dos 12 anos de estudo e novos indivíduos foram constantemente identificados na área. Os resultados sugerem que parte desta população depende substancialmente do habitat fornecido pela Baía de Sepetiba, tanto para alimentação quanto para fins de reprodução, apesar de haver indivíduos que pouco se utilizam desta área.

Estuarine dolphins, Sotalia guianensis (Van Bénéden, 1864), were identified in Sepetiba Bay (22º35'S, 44º03'W), state of Rio de Janeiro, Brazil, between February 1994 and July 2006 using the photo-identification method. A total of 72 surveys resulted in the identification and cataloguing of 217 individual dolphins. Seventy-nine (36%) were resighted at least once during the study period. The average interval between resightings was 40,6 ± 31,1 months. Large numbers of mother-and-calf pairs were recorded during the 12 years and new individuals were frequently encountered in the photographic records. These results suggest that part of the dolphin population is more consistently found in Sepetiba Bay, probably for feeding and reproduction, while other individuals use the Bay only sporadically.