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Sharma SP, Ghazi MG, Katdare S, Dasgupta N, Mondol S, Gupta SK, Hussain SA. Microsatellite analysis reveals low genetic diversity in managed populations of the critically endangered gharial (Gavialis gangeticus) in India. Sci Rep 2021; 11:5627. [PMID: 33707622 PMCID: PMC7970970 DOI: 10.1038/s41598-021-85201-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 02/25/2021] [Indexed: 01/31/2023] Open
Abstract
The gharial (Gavialis gangeticus) is a critically endangered crocodylian, endemic to the Indian subcontinent. The species has experienced severe population decline during the twentieth century owing to habitat loss, poaching, and mortalities in passive fishing. Its extant populations have largely recovered through translocation programmes initiated in 1975. Understanding the genetic status of these populations is crucial for evaluating the effectiveness of the ongoing conservation efforts. This study assessed the genetic diversity, population structure, and evidence of genetic bottlenecks of the two managed populations inhabiting the Chambal and Girwa Rivers, which hold nearly 80% of the global gharial populations. We used seven polymorphic nuclear microsatellite loci and a 520 bp partial fragment of the mitochondrial control region (CR). The overall mean allelic richness (Ar) was 2.80 ± 0.40, and the observed (Ho) and expected (He) heterozygosities were 0.40 ± 0.05 and 0.39 ± 0.05, respectively. We observed low levels of genetic differentiation between populations (FST = 0.039, P < 0.05; G'ST = 0.058, P < 0.05 Jost's D = 0.016, P < 0.05). The bottleneck analysis using the M ratio (Chambal = 0.31 ± 0.06; Girwa = 0.41 ± 0.12) suggested the presence of a genetic bottleneck in both populations. The mitochondrial CR also showed a low level of variation, with two haplotypes observed in the Girwa population. This study highlights the low level of genetic diversity in the two largest managed gharial populations in the wild. Hence, it is recommended to assess the genetic status of extant wild and captive gharial populations for planning future translocation programmes to ensure long-term survival in the wild.
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Affiliation(s)
- Surya Prasad Sharma
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India
| | | | - Suyash Katdare
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India
| | - Niladri Dasgupta
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India
| | - Samrat Mondol
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India
| | - Sandeep Kumar Gupta
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India
| | - Syed Ainul Hussain
- Wildlife Institute of India, Chandrabani, P.O. Box # 18, Dehra Dun, Uttarakhand, 248002, India.
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Abstract
The influence of kinship on animal cooperation is often unclear. Cooperating Asiatic lion coalitions are linearly hierarchical; male partners appropriate resources disproportionately. To investigate how kinship affect coalitionary dynamics, we combined microsatellite based genetic inferences with long-term genealogical records to measure relatedness between coalition partners of free-ranging lions in Gir, India. Large coalitions had higher likelihood of having sibling partners, while pairs were primarily unrelated. Fitness computations incorporating genetic relatedness revealed that low-ranking males in large coalitions were typically related to the dominant males and had fitness indices higher than single males, contrary to the previous understanding of this system based on indices derived from behavioural metrics alone. This demonstrates the indirect benefits to (related) males in large coalitions. Dominant males were found to 'lose less' if they lost mating opportunities to related partners versus unrelated males. From observations on territorial conflicts we show that while unrelated males cooperate, kin-selected benefits are ultimately essential for the maintenance of large coalitions. Although large coalitions maximised fitness as a group, demographic parameters limited their prevalence by restricting kin availability. Such demographic and behavioural constraints condition two-male coalitions to be the most attainable compromise for Gir lions.
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Affiliation(s)
- Stotra Chakrabarti
- Department of Fisheries, Wildlife & Conservation Biology, University of Minnesota, 2003 Buford Circle, 150 Skok Hall, St. Paul, MN, 55108, USA.
- Department of Animal Ecology & Conservation Biology, Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand, 248 001, India.
| | - Vishnupriya Kolipakam
- Department of Animal Ecology & Conservation Biology, Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand, 248 001, India
| | - Joseph K Bump
- Department of Fisheries, Wildlife & Conservation Biology, University of Minnesota, 2003 Buford Circle, 150 Skok Hall, St. Paul, MN, 55108, USA
| | - Yadvendradev V Jhala
- Department of Animal Ecology & Conservation Biology, Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand, 248 001, India.
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