Genetic Diversity of New World Crocodilians

Amavet, Patricia Susana; Zucoloto, Rodrigo Barban; Hrbek, Tomas; Farias, Izeni Pires

doi:10.1007/978-3-030-56383-7_5

Cited by 6 publications

(2 citation statements)

References 69 publications

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“…However, release of captive bred animals can contribute in increasing genetic diversity, decreasing xation of loci and reducing effects of genetic drift induced differentiation, provided the released animals are screened for their genetic structure 3,52 . Low heterozygosity in crocodiles is attributed to longevity, late maturation and generational overlaps 53 . However, traits such as longevity and delayed sexual maturity can result in retention of moderate genetic diversity in wild populations while masking effects of population decline such as genetic drift and low effective population sizes.…”

Section: Discussionmentioning

confidence: 99%

Anthropogenic restocking of gharial individuals prevents genetic isolation of gharial population in Girwa River, India by geographic barriers imposed by a barrage

Vashistha

Sharma

Khudsar

et al. 2021

Preprint

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Gharial (Gavialis gangeticus) is a critically endangered fresh water crocodile endemic to the Indian subcontinent. The species has suffered > 95% decline in population and habitat size. A small population of gharials comprising of 50 breeding adults is resident in a 20 Km stretch of the River Girwa in Katerniaghat wildlife sanctuary, India. Gharials in this 20 Km stretch have been genetically isolated since 1976 by a barrage that functions as a barrier to gene flow. A captive rear and release program has been initiated since 1979 under Project Crocodile for restocking declining wild gharial populations. Thousands of gharial eggs were collected from gharial populations at Girwa and Chambal Rivers. Hatchlings from the collected eggs were captive reared at a common location in Kukrail Gharial Centre, India and released back to multiple gharial populations including the isolated population at Girwa. This restocking programme was not preceded by a genetic screening of captive animals or wild populations to identify genetic diversity and genetic structure of both captive and wild animals. In this study we investigate whether release of captive reared gharials into the resident population at Girwa River has prevented genetic isolation caused due to barriers imposed by the barrage. Using a combination of empirical analysis using microsatellite markers and a systematic review of data from previous workers on molecular characterization of gharial populations, we analysed genetic differentiation in gharial populations at Girwa and Chambal. We found similar genetic variability in gharial populations of Girwa and Chambal. There was low inter population genetic differentiation and evidences of genetic migration between the two populations. Our findings indicate that anthropogenic intervention via release of captive animals has compensated for the genetic isolation in Girwa population caused by the barrage.

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Section: Discussionmentioning

confidence: 99%

Anthropogenic restocking of gharial individuals prevents genetic isolation of gharial population in Girwa River, India by geographic barriers imposed by a barrage

Vashistha

Sharma

Khudsar

et al. 2021

Preprint

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show abstract

“…It consists of the differences between individuals at different levels, such as morphological features, structure and chromosomal number, and polymorphisms of sequences of DNAs or proteins. Most estimations about genetic diversity have been made based on allele or genotypic frequency obtained by studying molecular markers of a population [ 11 , 12 ]. Increasing evidence shows that genetic diversity provides raw materials necessary for adaptive evolution [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

The General Trends of Genetic Diversity Change in Alien Plants’ Invasion

Han

Zhang

et al. 2023

Plants

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Genetic diversity is associated with invasion dynamics during establishment and expansion stages by affecting the viability and adaptive potential of exotics. There have been many reports on the comparison between the genetic diversity of invasive alien species (IAS) in and out of their native habitats, but the conclusions were usually inconsistent. In this work, a standard meta-analysis of the genetic diversity of 19 invasive plants based on 26 previous studies was carried out to investigate the general trend for the change of IASs’ genetic diversity during their invasion process and its real correlation with the invasion fate. Those 26 studies were screened from a total of 3557 peer-reviewed publications from the ISI Web of Science database during the period of January 2000 to May 2022. Based on the selected studies in this work, a general reduction of IASs’ genetic diversity was found in non-native populations compared to that in native ones, while the difference was not significant. This finding suggested that regardless of the change in genetic diversity, it had no substantial effect on the outcome of the invasion process. Therefore, genetic diversity might not serve as a reliable indicator for risk assessment and prediction of invasion dynamic prediction in the case of IASs.

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Not one but two: examining the genetic origin and characterization of the non-native spectacled caiman (Caiman crocodilus) in Florida

Parks,

Godfrey,

Gross

et al. 2023

Biol Invasions

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The US state of Florida is home to an alarmingly large number of invasive species, many of which have proven detrimental to native ecosystems. Biological invasions of reptiles in particular have been a major concern in recent years. The spectacled caiman (Caiman crocodilus) was first introduced from Latin America to Florida in the 1950’s. Given there are now established breeding populations across southern Florida, there are ongoing efforts to control them. Therefore, there is a need to understand this species’ natural history and introduction pathways. Previous studies have cited the Caribbean Coastal region of Colombia as a primary, and possibly exclusive, origin of C. crocodilus in Florida, and the species was identified as belonging to the C. c. fuscus molecular lineage. However, previous genetic sampling has been limited and may have been biased by small sample sizes and limited geographic scale. We collected 27 genetic samples from caimans captured in Florida, and sequenced the mitochondrial genes, Cytochrome oxidase I (COI) and Cytochrome B (CytB) for comparison with homologous gene fragments available for the species at GenBank. We found genetic evidence for multiple introduction events and the taxonomic classification of the Florida caimans as two distinct molecular lineages (C. c. fuscus and C. c. crocodilus) originating from at least two different regions: the Magdalena River Basin in Colombia and the Upper Branco River Basin in northern Brazil. This study helps to elucidate the genetic history of Florida caimans and provides valuable insight for population management of the species in Florida.

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Genetic Diversity of New World Crocodilians

Cited by 6 publications

References 69 publications

Anthropogenic restocking of gharial individuals prevents genetic isolation of gharial population in Girwa River, India by geographic barriers imposed by a barrage

Anthropogenic restocking of gharial individuals prevents genetic isolation of gharial population in Girwa River, India by geographic barriers imposed by a barrage

The General Trends of Genetic Diversity Change in Alien Plants’ Invasion

Not one but two: examining the genetic origin and characterization of the non-native spectacled caiman (Caiman crocodilus) in Florida

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