Bioscience Evidence 2025, Vol.15, No.6, 291-302 http://bioscipublisher.com/index.php/be 293 and southeastward from the border of China/Indochinese Peninsula. Both experienced the founder effect, population bottleneck and localization adaptation during their migration processes. Marsh buffaloes exhibit a strong systemic geographical structure and extremely low gene flow. River buffaloes are relatively weak in geographical structure, but more abundant in phenotype and genetic diversity, which is related to breed formation, hybrid breeding and the selection of traits such as milk production and draft capacity (Si et al., 2024; Dutta et al., 2020). After river buffaloes entered the Mediterranean region and South America, the local groups further mixed and formed unique regional types. 3 Genetic Diversity of Wild Water Buffaloes 3.1 Current protection status and population bottleneck The wild water buffalo (Bubalus arnee) is an endangered animal. There are fewer than 4 000 left in the world. About 90% of them stay in two small and separate areas in India, in Assam and Chhattisgarh (Pacha et al., 2021). These buffaloes face many problems. Their homes are getting smaller or damaged. People still hunt them. Livestock bring diseases. They also mix and breed with domestic buffalo. The group in central India is in very bad shape. It is almost gone. It needs fast help through protection and reintroduction work (Bora et al., 2024). In Nepal, the only wild group lives in the Koshi Tappu Wildlife Reserve. But it also faces human pressure, poor living conditions, and gene mixing with domestic buffalo (Khulal et al., 2021). 3.2 Genetic variation patterns revealed by mitochondrial DNA, microsatellites and SNP markers Sequencing results of the mitochondrial genome of wild buffaloes revealed genetic similarities between the two major populations in India, but significant differences from domesticated buffaloes, especially in the obvious structural changes of multiple tRNA secondary structures (Pacha et al., 2021). Bayesian phylogenetic tree analysis indicates that wild buffaloes and domestic buffaloes form sister groups, showing a close evolutionary relationship and revealing clear genetic differentiation. Even though the wild populations are small, they still keep some genetic variation, but it is usually lower than that of domestic breeds. Studies based on SNPs are still limited, but the current findings already show a trend of genetic changes caused by past bottlenecks. Using different types of molecular markers together is very important for checking genetic health, finding hybrid events, and helping with conservation work (Si et al., 2024). 3.3 Evidence of inbreeding, fragmentation and genetic drift Studies show that many wild buffalo groups do not match Hardy–Weinberg balance, and this means their mating is not fully random. It also suggests that inbreeding may be taking place (Pacha et al., 2021). The presence of back-crossed animals and the ongoing mix with domestic buffalo make the genetic situation even harder to understand. Over time, this mixing can reduce the wild genetic types and may bring harmful traits into wild herds (Khulal et al., 2021). When the population goes through a bottleneck, genetic drift becomes stronger. As a result, some alleles may disappear just by chance, and the overall genetic diversity drops (Bora et al., 2024). 4 The Genetic Diversity of Four Domestic Water Buffaloes 4.1 Comparison between river water buffaloes (such as Indian and Pakistani breeds) and marsh water buffaloes (such as Southeast Asian breeds) River-type buffalo mainly live in South Asia, the Middle East, and the Mediterranean. They are well known for producing a lot of milk. In countries like India, Pakistan, and Italy, they play an important role in the dairy industry. In contrast, swamp-type buffalo are common in Southeast Asia and southern China. They are strong and can live well in wetland areas, so people traditionally use them as working animals in rice fields (Zhong et al., 2020). The two types of buffalo also have different chromosome numbers. River-type buffalo have 50 chromosomes, while swamp-type buffalo have 48. They also show clear differences in appearance and genetic structure. River-type buffalo include many breeds, and their body size, milk yield, and adaptability vary a lot. Swamp-type buffalo, although spread across a wide area, look very similar to each other and show more uniform traits.
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