Biology subjects

Dalton, D. L.

Publications and source records attributed to Dalton, D. L..

2 recordsLinked to original sources

bioRxiv2020

Conservation Genomic Analyses of African and Asiatic Cheetahs (Acinonyx jubatus) Across Their Current and Historic Species Range.

Cheetahs (Acinonyx jubatus) are majestic carnivores and the fastest land animals; yet, they are quickly heading towards an uncertain future. Threatened by habitat loss, human-interactions and illegal trafficking, there are only approximately 7,100 individuals remaining in the wild. Cheetahs used to roam large parts of Africa, and Western and Southern Asia. Today they are confined to about 9% of their original distribution. To investigate their genetic diversity and conservation status, we generated genome-wide data from historical and modern samples of all four currently recognized subspecies, along with mitochondrial DNA (mtDNA) and major histo-compatibility complex (MHC) data. We found clear genetic differentiation between the sub-species, thus refuting earlier assumptions that cheetahs show only little population differentiation. Our genome-wide nuclear data indicate that cheetahs from East Africa may be more closely related to A. j. soemmeringii than they are to A. j. jubatus. This supports the need for further research on the classification of cheetah subspecies, as East African cheetahs are currently included in the Southern Africa subspecies, A. j. jubatus. We detected stronger inbreeding in individuals of the Critically Endangered A. j. venaticus (Iran) and A. j. hecki (Northwest Africa), and show that overall genome-wide heterozygosity in cheetah is lower than that reported for other threatened and endangered felids, such as tigers and lions. Furthermore, we show that MHC class II diversity in cheetahs is generally higher than previously reported, but still lower than in other felids. Our results provide new and important information for efficient genetic monitoring, subspecies assignments and evidence-based conservation policy decisions.

evolutionary biology↗

bioRxiv2019

Assessing introgressive hybridization in roan antelope (Hippotragus equinus): Lessons from South Africa

Biological diversity is being lost at unprecedented rates, with admixture and introgression presenting major threats to species conservation. To this end, our ability to accurately identify introgression is critical to manage species, obtain insights into evolutionary processes, and ultimately contribute to the Aichi Targets developed under the Convention on Biological Diversity. A case in hand concerns roan antelope, one of Africas most iconic large mammal species. Despite their large size, these antelope are sensitive to habitat disturbance and interspecific competition, leading to the species being listed as Least Concern but with decreasing population trends, and as extinct over parts of its range. Molecular research identified the presence of two evolutionary significant units across their sub-Saharan range, corresponding to a West African lineage and a second larger group which includes animals from East, Central and Southern Africa. Within South Africa, one of the remaining bastions with increasing population sizes, there are a number of West African roan antelope populations on private farms, and concerns are that these animals hybridize with roan that naturally occur in the southern African region. We used a suite of 27 microsatellite markers to conduct admixture analysis. Our results unequivocally indicate evidence of hybridization, with our developed tests able to accurately identify F1, F2 and non-admixed individuals at threshold values of qi = 0.20 and qi = 0.15, although further backcrosses were not always detectable. Our study is the first to confirm ongoing hybridization in this iconic African antelope, and we provide recommendations for the future conservation and management of this species.

zoology↗