Caiman latirostris (broad-snouted caiman) is a crocodilian species from Argentina subject of mana... more Caiman latirostris (broad-snouted caiman) is a crocodilian species from Argentina subject of management plans. The goal of this study was estimating the distribution of genetic variability using RAPD markers and quantitative traits in wild populations of C. latirostris from Santa Fe province, Argentina. We sampled animals from four populations to obtain DNA and morphometric measurements. Eight RAPD primers were used and PCR products were analyzed on 4% polyacrylamide gels stained with silver nitrate. Eleven allometric measurements were obtained in animals within 48 hr after birth. We were able to reveal a relatively high number of variable markers in the studied populations. Our estimates of polymorphism and heterozygosity are higher than recorded values in other crocodilians using isozymes, the studied populations showed low levels of gene flow and some population subdivision. The study of quantitative traits conducted by nested analysis of variance and principal component analysis indicated higher levels of variance among nests within populations than among populations. We found that some head measurements have the highest contribution to morphological differences among populations; this fact could support the role of these traits in reproductive or feeding behavior. Estimated genetic differentiation value (F(ST)) among populations was higher than quantitative trait differentiation value (Q(ST)), suggesting a higher contribution of neutral than adaptive loci to the genetic differentiation among populations. Quantitative traits are probably more related with fitness and the differentiation among populations remained relatively lower. The high heritability estimated for some traits indicates great potential to improve them in management plans.
The utilization of RAPD and ISSR molecular markers is proposed to initiate studies of genetic var... more The utilization of RAPD and ISSR molecular markers is proposed to initiate studies of genetic variability in Phrynops hilarii (Chelidae) and Trachemys dorbigni (Emydidae), two species of fresh water turtles distributed in South America. Three primers of RAPD and four of ISSR were selected and the ampliifed products of these markers were evaluated by electrophoretic runs in agarose and polyacrylamide gels. The levels of heterozygosity, Shannon index and different allele numbers were slightly higher in P. hilarii for both types of markers. Levels of polymorphism were also higher in P. hilarii than T. dorbigni and both were elevated compared to those recorded for other species. The fact that similar results were obtained with both types of markers for all estimates of diversity highlights the usefulness and validity of the RAPD technique. The molecular markers used were found potentially useful for analysing future temporal and spatial distribution of genetic diversity in both species, expanding scales work.
Genetic diversity is one of the most important attributes of any population; it is defined as the... more 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
Over the last 8 years, a group of 18 former crocodile hunters, known as “caimaneros” at Cispatá B... more Over the last 8 years, a group of 18 former crocodile hunters, known as “caimaneros” at Cispatá Bay, Colombia have turned conservationists, joining a project to save the critically endangered American crocodile (Crocodylus acutus). The project includes recovery programs, population monitoring, biological studies on sustainable use, education and communication and it was created a capacity-building program since 2004, in order to promote local livelihoods and give the reptiles a fighting chance. Crocodile eggs are hatched in incubators and reared until they are large enough to release into the wild. As the project is based on sustainable use of the population it will need ongoing monitoring and research that will help form a sound management plan. The project is supported by the Environmental Regional Authority CVS and is part of the integrated management plan for local mangroves on which many people depend for livelihoods. Preliminary Management Plan for the Conservation of Populati...
Microsatellites are genomic sequences comprised of tandem repeats of short nucleotide motifs wide... more Microsatellites are genomic sequences comprised of tandem repeats of short nucleotide motifs widely used as molecular markers in population genetics. FullSSR is a new bioinformatic tool for microsatellite (SSR) loci detection and primer design using genomic data from NGS assay. The software was tested with 2000 sequences of Oryza sativa shotgun sequencing project from the National Center of Biotechnology Information Trace Archive and with partial genome sequencing with ROCHE 454® from Caiman latirostris, Salvator merianae, Aegla platensis, and Zilchiopsis collastinensis. FullSSR performance was compared against other similar SSR search programs. The results of the use of this kind of approach depend on the parameters set by the user. In addition, results can be affected by the analyzed sequences because of differences among the genomes. FullSSR simplifies the detection of SSRs and primer design on a big data set. The command line interface of FullSSR was intended to be used as part ...
Caiman latirostris (yacare overo) es una de las dos especies de cocodrilianos citadas para nuestr... more Caiman latirostris (yacare overo) es una de las dos especies de cocodrilianos citadas para nuestro pais. Sus poblaciones silvestres son objeto de manejo en Argentina, mediante programas que utilizan el sistema de ranching (cosecha de huevos silvestres para cria en granjas), para su uso sustentable y la conservacion de su habitat. C. latirostris, en nuestro pais, se encuentra en el Apendice II de CITES, el cual permite el comercio regulado de su cuero y carne, y se ha convertido en una especie de gran importancia comercial, a nivel nacional e internacional. Esta tesis incluye estudios genetico-poblacionales del yacare overo en la provincia de Santa Fe, Argentina. Se realizaron analisis de variabilidad, diferenciacion y estructura genetica empleando isoenzimas, marcadores RAPD y caracteres morfometricos, y un estudio de paternidad utilizando marcadores microsatelites. Los resultados obtenidos indican que las poblaciones analizadas de yacare overo poseen valores de variabilidad genetic...
The chapter gives an introductory overview on the biology of the 11 species of crocodilians inhab... more The chapter gives an introductory overview on the biology of the 11 species of crocodilians inhabiting the Americas. Geographical distribution is broadly discussed in the light of biogeographical and evolutionary origins. As a broad generalization, crocodilians are morphologically, genetically, and ecologically conservative and show a high dispersal ability, which together complicate the delimitation of species boundaries. Furthermore, distinct clades of crocodilians are a result of environmental selection for different adaptive characteristics. Gene flow occurs between clades, but distinct morphological varieties are sometimes a result of environmental filters. Thus, many taxa of crocodilians can be considered ecological species. Reproductive characteristics, such as nest-site choice and female reproductive output, influence reproductive success and thus population trends, so we discuss reproductive and habitat characteristics in the light of conservation genetics. Finally, the status of crocodilians is discussed both in terms of past hunting pressure and current conservation and management initiatives. In general, crocodilians can look after themselves if they have sufficient habitat, but some species are critically endangered by hunting, even though much of their original habitat remains intact. Conservation actions must be applied locally, taking into account threats and dispersal between source and sink populations. Given the difficulty of studying the F. Villamarín (*) Grupo de Biogeografía y Ecología Espacial (BioGeoE2). Universidad Regional Amazónica Ikiam, Km 7 vía Muyuna., Tena, Ecuador A. H. Escobedo-Galván Centro Universitario de la Costa, Universidad de Guadalajara, Puerto Vallarta, Jalisco, Mexico P. Siroski Laboratorio de Ecología Molecular Aplicada-ICiVet UNL/ CONICET, Santa Fe, Argentina e-mail: psiroski@fcv.unl.edu.ar W. E. Magnusson Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil e-mail: bill@inpa.gov.br
The yacare caiman (Caiman yacare) is a reptile from South America and 1 of the 2 crocodilian spec... more The yacare caiman (Caiman yacare) is a reptile from South America and 1 of the 2 crocodilian species present in Argentina. The degradation of their natural habitat and strong hunting pressure led to a sharp numerical decline of wild populations. Nowadays, C. yacare is included in Appendix II of CITES, and ranching practices in some areas in Argentina are helping hatching success. In this context, it is important to better understand the population structure and mating system of the species. To do this, we amplified 10 microsatellite markers (SSRs) in 148 individuals of 13 C. yacare nests. All of the markers were polymorphic with 2–12 alleles per locus, with allelic sizes ranging between 154 and 400 bp and medium levels of polymorphism (Ho = 0.152–0.551 and He = 0.221–0.621). We were able to determine the maternal genotype in 9 out of 13 nests. In 6 of them we found more than 1 paternal genotype, with a maximum of 3 fathers for a single nest. This study is the first to provide eviden...
The genus Salvator is widely distributed throughout South America. In Argentina, the species most... more The genus Salvator is widely distributed throughout South America. In Argentina, the species most abundant widely distributed is Salvator merianae. Particularly in Santa Fe province, the area occupied by populations of these lizards overlaps with areas where agriculture was extended. With the aim of established baseline values for four immunologic biomarkers widely used, 36 tegu lizards were evaluated tacking into account different age classes and both sexes. Total leukocyte counts were not different between age classes. Of the leucocytes count, eosinophils levels were higher in neonates compared with juvenile and adults; nevertheless, the heterophils group was the most prevalent leukocyte in the peripheral blood in all age classes. Lymphocytes, monocytes, heterophils, azurophils and basophils levels did not differ with age. Natural antibodies titres were higher in the adults compared with neonates and juveniles lizards. Lastly, complement system activity was low in neonates compare...
Caiman latirostris (broad-snouted caiman) is a crocodilian species from Argentina subject of mana... more Caiman latirostris (broad-snouted caiman) is a crocodilian species from Argentina subject of management plans. The goal of this study was estimating the distribution of genetic variability using RAPD markers and quantitative traits in wild populations of C. latirostris from Santa Fe province, Argentina. We sampled animals from four populations to obtain DNA and morphometric measurements. Eight RAPD primers were used and PCR products were analyzed on 4% polyacrylamide gels stained with silver nitrate. Eleven allometric measurements were obtained in animals within 48 hr after birth. We were able to reveal a relatively high number of variable markers in the studied populations. Our estimates of polymorphism and heterozygosity are higher than recorded values in other crocodilians using isozymes, the studied populations showed low levels of gene flow and some population subdivision. The study of quantitative traits conducted by nested analysis of variance and principal component analysis indicated higher levels of variance among nests within populations than among populations. We found that some head measurements have the highest contribution to morphological differences among populations; this fact could support the role of these traits in reproductive or feeding behavior. Estimated genetic differentiation value (F(ST)) among populations was higher than quantitative trait differentiation value (Q(ST)), suggesting a higher contribution of neutral than adaptive loci to the genetic differentiation among populations. Quantitative traits are probably more related with fitness and the differentiation among populations remained relatively lower. The high heritability estimated for some traits indicates great potential to improve them in management plans.
The utilization of RAPD and ISSR molecular markers is proposed to initiate studies of genetic var... more The utilization of RAPD and ISSR molecular markers is proposed to initiate studies of genetic variability in Phrynops hilarii (Chelidae) and Trachemys dorbigni (Emydidae), two species of fresh water turtles distributed in South America. Three primers of RAPD and four of ISSR were selected and the ampliifed products of these markers were evaluated by electrophoretic runs in agarose and polyacrylamide gels. The levels of heterozygosity, Shannon index and different allele numbers were slightly higher in P. hilarii for both types of markers. Levels of polymorphism were also higher in P. hilarii than T. dorbigni and both were elevated compared to those recorded for other species. The fact that similar results were obtained with both types of markers for all estimates of diversity highlights the usefulness and validity of the RAPD technique. The molecular markers used were found potentially useful for analysing future temporal and spatial distribution of genetic diversity in both species, expanding scales work.
Genetic diversity is one of the most important attributes of any population; it is defined as the... more 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
Over the last 8 years, a group of 18 former crocodile hunters, known as “caimaneros” at Cispatá B... more Over the last 8 years, a group of 18 former crocodile hunters, known as “caimaneros” at Cispatá Bay, Colombia have turned conservationists, joining a project to save the critically endangered American crocodile (Crocodylus acutus). The project includes recovery programs, population monitoring, biological studies on sustainable use, education and communication and it was created a capacity-building program since 2004, in order to promote local livelihoods and give the reptiles a fighting chance. Crocodile eggs are hatched in incubators and reared until they are large enough to release into the wild. As the project is based on sustainable use of the population it will need ongoing monitoring and research that will help form a sound management plan. The project is supported by the Environmental Regional Authority CVS and is part of the integrated management plan for local mangroves on which many people depend for livelihoods. Preliminary Management Plan for the Conservation of Populati...
Microsatellites are genomic sequences comprised of tandem repeats of short nucleotide motifs wide... more Microsatellites are genomic sequences comprised of tandem repeats of short nucleotide motifs widely used as molecular markers in population genetics. FullSSR is a new bioinformatic tool for microsatellite (SSR) loci detection and primer design using genomic data from NGS assay. The software was tested with 2000 sequences of Oryza sativa shotgun sequencing project from the National Center of Biotechnology Information Trace Archive and with partial genome sequencing with ROCHE 454® from Caiman latirostris, Salvator merianae, Aegla platensis, and Zilchiopsis collastinensis. FullSSR performance was compared against other similar SSR search programs. The results of the use of this kind of approach depend on the parameters set by the user. In addition, results can be affected by the analyzed sequences because of differences among the genomes. FullSSR simplifies the detection of SSRs and primer design on a big data set. The command line interface of FullSSR was intended to be used as part ...
Caiman latirostris (yacare overo) es una de las dos especies de cocodrilianos citadas para nuestr... more Caiman latirostris (yacare overo) es una de las dos especies de cocodrilianos citadas para nuestro pais. Sus poblaciones silvestres son objeto de manejo en Argentina, mediante programas que utilizan el sistema de ranching (cosecha de huevos silvestres para cria en granjas), para su uso sustentable y la conservacion de su habitat. C. latirostris, en nuestro pais, se encuentra en el Apendice II de CITES, el cual permite el comercio regulado de su cuero y carne, y se ha convertido en una especie de gran importancia comercial, a nivel nacional e internacional. Esta tesis incluye estudios genetico-poblacionales del yacare overo en la provincia de Santa Fe, Argentina. Se realizaron analisis de variabilidad, diferenciacion y estructura genetica empleando isoenzimas, marcadores RAPD y caracteres morfometricos, y un estudio de paternidad utilizando marcadores microsatelites. Los resultados obtenidos indican que las poblaciones analizadas de yacare overo poseen valores de variabilidad genetic...
The chapter gives an introductory overview on the biology of the 11 species of crocodilians inhab... more The chapter gives an introductory overview on the biology of the 11 species of crocodilians inhabiting the Americas. Geographical distribution is broadly discussed in the light of biogeographical and evolutionary origins. As a broad generalization, crocodilians are morphologically, genetically, and ecologically conservative and show a high dispersal ability, which together complicate the delimitation of species boundaries. Furthermore, distinct clades of crocodilians are a result of environmental selection for different adaptive characteristics. Gene flow occurs between clades, but distinct morphological varieties are sometimes a result of environmental filters. Thus, many taxa of crocodilians can be considered ecological species. Reproductive characteristics, such as nest-site choice and female reproductive output, influence reproductive success and thus population trends, so we discuss reproductive and habitat characteristics in the light of conservation genetics. Finally, the status of crocodilians is discussed both in terms of past hunting pressure and current conservation and management initiatives. In general, crocodilians can look after themselves if they have sufficient habitat, but some species are critically endangered by hunting, even though much of their original habitat remains intact. Conservation actions must be applied locally, taking into account threats and dispersal between source and sink populations. Given the difficulty of studying the F. Villamarín (*) Grupo de Biogeografía y Ecología Espacial (BioGeoE2). Universidad Regional Amazónica Ikiam, Km 7 vía Muyuna., Tena, Ecuador A. H. Escobedo-Galván Centro Universitario de la Costa, Universidad de Guadalajara, Puerto Vallarta, Jalisco, Mexico P. Siroski Laboratorio de Ecología Molecular Aplicada-ICiVet UNL/ CONICET, Santa Fe, Argentina e-mail: psiroski@fcv.unl.edu.ar W. E. Magnusson Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil e-mail: bill@inpa.gov.br
The yacare caiman (Caiman yacare) is a reptile from South America and 1 of the 2 crocodilian spec... more The yacare caiman (Caiman yacare) is a reptile from South America and 1 of the 2 crocodilian species present in Argentina. The degradation of their natural habitat and strong hunting pressure led to a sharp numerical decline of wild populations. Nowadays, C. yacare is included in Appendix II of CITES, and ranching practices in some areas in Argentina are helping hatching success. In this context, it is important to better understand the population structure and mating system of the species. To do this, we amplified 10 microsatellite markers (SSRs) in 148 individuals of 13 C. yacare nests. All of the markers were polymorphic with 2–12 alleles per locus, with allelic sizes ranging between 154 and 400 bp and medium levels of polymorphism (Ho = 0.152–0.551 and He = 0.221–0.621). We were able to determine the maternal genotype in 9 out of 13 nests. In 6 of them we found more than 1 paternal genotype, with a maximum of 3 fathers for a single nest. This study is the first to provide eviden...
The genus Salvator is widely distributed throughout South America. In Argentina, the species most... more The genus Salvator is widely distributed throughout South America. In Argentina, the species most abundant widely distributed is Salvator merianae. Particularly in Santa Fe province, the area occupied by populations of these lizards overlaps with areas where agriculture was extended. With the aim of established baseline values for four immunologic biomarkers widely used, 36 tegu lizards were evaluated tacking into account different age classes and both sexes. Total leukocyte counts were not different between age classes. Of the leucocytes count, eosinophils levels were higher in neonates compared with juvenile and adults; nevertheless, the heterophils group was the most prevalent leukocyte in the peripheral blood in all age classes. Lymphocytes, monocytes, heterophils, azurophils and basophils levels did not differ with age. Natural antibodies titres were higher in the adults compared with neonates and juveniles lizards. Lastly, complement system activity was low in neonates compare...
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