Bioscience Evidence 2025, Vol.15, No.6, 291-302 http://bioscipublisher.com/index.php/be 294 Whole genome sequencing and SNP chip analysis further confirmed the segregation of the two types of buffaloes in systematic clustering (Si et al., 2024; Lu et al., 2020; Luo et al., 2020; Sun et al., 2020). Among river buffaloes, varieties such as Murrah, Nili-Ravi and Mediterranean exhibit high genetic diversity and are subject to intensive selection centered on milk-use traits. Marshland buffaloes also maintain high diversity in both maternal and paternal genetic lineages, but the phenotypic differences among populations are relatively small. This is likely related to their main use as draft animals and the relatively weak artificial selection pressure. 4.2 Genetic variations of different varieties and regional populations River buffaloes, especially those from India and Pakistan, generally show high genetic diversity, which has been confirmed by microsatellite markers, SNP data and genome-wide analysis (Macciotta et al., 2021). Studies on Indian varieties such as Murrah, Banni and Jaffarabadi have found that the diversity within these groups is rich, while the differences among varieties are moderate (Dutta et al., 2020; Rehman et al., 2021). The Mediterranean and European buffalo populations originated from the ancient introduction of river buffaloes and formed unique genotypes in regions such as Hungary and Germany, which is closely related to hybridization and local adaptation (Noce et al., 2021). Although swamp buffalo are very different from river buffalo at the genetic level, they show clear geographic differences. In some isolated areas of Southeast Asia and China, their genetic diversity inside the population is quite low (Lu et al., 2020). The highest genetic diversity is found near the China–Indochina border, which is seen as an early domestication center. As the buffalo moved north or south from this area, their genetic diversity became lower. The body shape and look of swamp buffalo are quite similar in different places. This may mean that their daily work and the environment around them limit how much their traits can change. But at the molecular level, they still have a lot of genetic variation. In some areas, certain groups also have special haplotypes and alleles. This shows that protecting local genetic resources is very important (Saputra et al., 2021). 4.3 The Influence of artificial selection, breeding practice and domestication on genetic structure In river buffalo, people have focused on selecting animals with high milk yield, good reproduction, and strong disease resistance. After many years, this made some specialized dairy breeds that now show their own genetic patterns. Genomic work has found clear selection signals in several genes. For example, CSN2 is related to milk traits, MC1Raffects coat color, and other genes are linked to reproduction. These signals are very strong in breeds like the Italian Mediterranean and the Indian Murrah (Sun et al., 2020; Si et al., 2024; Pauciullo et al., 2025). Such long-term selection increased the number of good alleles in these breeds, but it also reduced overall genetic diversity in some high-production groups, especially those living at the edge of their range, such as the Italian river buffalo. In contrast, swamp buffalo have faced much weaker artificial selection. Their breeding has focused more on keeping working ability and environmental adaptability, not improving production traits. Because the two types of buffalo were domesticated in different places and at different times, and later moved into new areas with different environments, they slowly developed their own genetic differences. Over time, they formed clear and separate population structures (Lu et al., 2020; Luo et al., 2020). New genomic tools, such as SNP chips and whole-genome sequencing, make it easier to find regions that may be under selection. These tools also help scientists look back at the population history of domestic buffalo and see how human activities have influenced their development (Macciotta et al., 2021; Rehman et al., 2021). A key challenge today is how to improve important traits while still keeping enough genetic diversity in buffalo around the world. 4.4 The role of gene flow, genetic infiltration and variety improvement projects In the Philippines and Brazil, both types of buffaloes live in the same areas. Because of old and recent movement of animals, and because people sometimes cross them on purpose, their genes have become mixed (Luo et al., 2020). Genomic studies also show signs of hybridization in these groups. Some genes related to useful traits, like higher milk yield, often move from one type to the other. It is also common to bring fluvial-type genes into marsh-type buffalo groups.
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