Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes

The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described

Molecular Phylogenetics of the New-World Crocodylia

During the late twentieth and early twenty-first centuries, there has been a revolution in evolutionary biology. Traditional methods that had been applied to understanding relationships and natural history for hundreds of years have been supplemented (and sometimes replaced) by biochemical and molecular techniques that now allow us to examine the entire genomes of non-model organisms. Herein we review the use of these new technologies as they apply to crocodylians in general and specifically to the New-World members of the Alligatoridae and Crocodylidae. While generally concordant with traditional analyses, in some cases they have permitted cryptic species to be recognized. In addition, they have allowed crocodylian biologists to detect hybridization events between species, both in captivity and in the wild, that would not have been possible before their use. Hybridization may lead to the formation of new species, but it may also allow a common species to “swamp out” a rarer one. Because there appears to be little hybrid dysgenesis between many of the potential hybridizing forms, hybridization is potentially a serious problem for several New-World species

Genetic Diversity of New World Crocodilians

Genetic diversity is one of the most important attributes of any population; it is defined as the variation in the amount of genetic information within and among individuals of a population, species, assemblage, or community. It can be expressed as differences between individuals at different levels, such as morphological features, structure and chromosomal number, and polymorphisms of sequences of DNA or proteins. An assessment of genetic diversity is fundamental to population genetic studies and has extremely important applications in conservation biology and the development of management and sustainable use plans. This chapter discusses the main indices that allow analyzing genetic variability and population structure of New World crocodilian populations, the methodologies used to estimate these indices, and the principal population genetic data available for these species. The effective population size concept is also discussed, a fundamental parameter in the study of principally those crocodile populations that have been drastically reduced in size and/or suffered fragmentation of their environments.Fil: Amavet, Patricia Susana. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Barban Zucoloto, Rodrigo. Universidade Federal da Bahia; BrasilFil: Hrbek, Tomas. Universidad Federal del Amazonas.; BrasilFil: Pires Farias, Izeni. Universidad Federal del Amazonas.; Brasi