Ecological Genetics and Genomics 23 (2022) 100121 Available online 22 April 2022 2405-9854/© 2022 Elsevier Inc. All rights reserved. Genetic differences among the species of genus Aulonocara and related genera of Malawian cichlids Shaharior Hashem a, b, * , Koichiro Kawai a , Patrick Senam Kof Fatsi c , Atsuya Kodama a , Ebenezer Koranteng Appiah a , Chogo Ogasawara a , Hidetoshi Saito a a Laboratory of Aquatic Ecology, Department of Bioresource Science, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi- hiroshima, Hiroshima, 739-8528, Japan b Department of Aquaculture, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh c Council for Scientifc and Industrial Research Institute, Water Research Institute, P.O. Box M 32, Accra, Ghana A R T I C L E INFO Keywords: Cichlids Genetic diversity Haplotype network Lake Malawi Mitochondrial DNA ABSTRACT In this study, our aim was to understand the genetic relationships between wild or bred individuals of a large fsh group from Lake Malawi, genus Aulonocara, and related genera. The mtDNA control region was sequenced in 35 individuals representing 16 species from the genera Aulonocara and Sciaenochromis, and 15 species from the other 12 genera, including mbuna and non-mbuna. In a genetic tree, constructed with the Kimura-2 parameter as a distance, using the neighbor-joining method, many species of the genus Aulonocara formed a clade with mbuna, while only two species formed another clade with non-mbuna species. Similarly, Sciaenochromis fryeri was a member of a clade by mbuna, while S. sp. nyassae was a member of a clade formed by non-mbuna. Among the Aulonocara species, A. steveni and A. sp. ‘Lwanda’ were estimated to be relatively close to their ancestors using network analysis. Some individuals of A. hansbaenschi and S. fryeri bred in Asia were found to be far from purely bred ones. These results suggest the possibility of generating the genera Aulonocara and Sciaenochromis by hy- bridization between mbuna and non-mbuna, and indicate that there are some genetic disturbances within the species of these genera caused by human activities. 1. Introduction Cichlidae (Order: Perciformes) is a family of bony fshes (perch-like fshes) [1]. Cichlid fshes are among the fnest model systems for studying biological diversifcation [2,3]. Many cichlid fsh species have been identifed in three Great Lakes of east Africa: Lakes Malawi, Tan- ganyika, and Victoria. The east African Great Lakes, the hotspots of their biodiversity alone, contain more than 1500 endemic species [4,5] and have therefore been the focus of numerous studies. Cichlids are distin- guished by their high morphological diversity, which allows them to occupy many niches. They are excellent examples of a group of fsh that has undergone swift adaptive radiation (reviewed in Refs. [6–8]). As the application of molecular techniques has gained acceptance among evolutionary biologists, it has become possible to elucidate the mechanisms responsible for the emergence of novel species more pre- cisely [9–13]. Even after signifcant advances in the feld, the question remains as to whether speciation always requires geographic separation or can evolve in a situation of geographical coexistence in spite of gene fow [14–19]. The duration associated with the diversifcation of these species as- semblages is very short [20]. Cichlids are found in lacustrine habitats throughout east Africa, where they form large monophyletic species groupings with up to hundred endemic species [21,22]. Biogeographical and phylogeographical studies can provide information on whether speciation needs ample geographic isolation by revealing the historical and current gene fow among populations and incipient species [23]. Biological, ecological, and biogeographical conditions at the time of the origin of a species may have changed over time and possibly differ today, which is considered a problem in speciation research [24,25]. The study of incipient species and lineages that are in the process of splitting is a better way to understand speciation [12]. It is mandatory to gather information on the phylogeography and evolutionary history of the involved species and populations to make inferences about the correlates or causes of any speciation event [26,27]. Adaptive radiations are prime systems for studying these factors, as they show a diversity of ecological adaptations. This process involves * Corresponding author. Department of Aquaculture, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh. E-mail address: shaharior@bau.edu.bd (S. Hashem). Contents lists available at ScienceDirect Ecological Genetics and Genomics journal homepage: www.elsevier.com/locate/egg https://doi.org/10.1016/j.egg.2022.100121 Received 18 October 2021; Received in revised form 23 March 2022; Accepted 15 April 2022