Flexibility of life to survive limitations: oral disc forms in the Tashan Cave barb Garra tashanensis

• Published in: Environmental biology of fishes Vol. 106; no. 11; pp. 2083 - 2092
• Main Authors: Hashemzadeh Segherloo, Iraj, Najafi Chaloshtory, Sajad, Yasser, Amaal Gh, Naser, Murtada D., Normandeau, Eric, Mashtizadeh, Amirhossein, Elmi, Amirmohammad, Sedighi, Omid, Changizi, Alieh, Hallerman, Eric, Bernatchez, Louis
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.11.2023; Springer Nature B.V
• Subjects: Animal Systematics/Taxonomy/Biogeography; Biodiversity; Biomedical and Life Sciences; Caves; Coexistence; Competitors; Differentiation; Ecological effects; Environment; Fish; Fishing; Freshwater & Marine Ecology; Garra; Genetic analysis; Genetic structure; genetic variation; Genomes; genomics; Genotype & phenotype; Genotyping; genotyping by sequencing; Iran; Life Sciences; Mitochondrial DNA; Morphology; morphs; Nature Conservation; nuclear genome; Population; Predators; Reproductive isolation; Speciation; Survival; Sympatric populations; sympatric speciation; Taxonomy; Zoology; Iran; Character release; Tashan Cave barb; Genome; Relaxed selection; Radiation
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-023-01475-1

In this study, we analyzed nuclear DNA (nDNA) variation by means of genotyping-by-sequencing (GBS) of three disc-bearing and seven non-disc-bearing Garra tashanensis from the Tashan Cave in Iran to clarify their systematic and ecological relationships. We performed genetic differentiation, NeighborNet, Admixture, and principal component analyses on genomic data. Admixture and principal component analyses revealed clear genetic differentiation between disc-bearing and non-disc-bearing morphotypes, which was not detected by mtDNA markers in previous work. However, there was a non-disc-bearing individual that clustered with disc-bearing individuals. Based on the results of this study, the most parsimonious justification for coexistence of disc-bearing and non-disc-bearing forms of Garra in Tashan Cave is a combination of mechanisms similar to character release (intra-specific morphological diversification to exploit a wider range of habitats in the absence of competitors or predators) and relaxed selection (no more selective advantage for a previously advantageous trait as a result of ecological changes). The detected genetic structure may be an indication of reproductive isolation between the two groups. These data imply that the respective forms of the Tashan Cave barb could be a case of ongoing sympatric speciation, but also that disc form cannot be used as a taxonomic character for Tashan Cave barb forms.