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Simple Summary: Phan Rang sheep is a term used to collectively refer to the sheep raised in the central Vietnam provinces of Ninh Thuan and Binh Thuan. Given the extreme weather conditions of their habitat, Phan Rang sheep are assumed to be heat-resilient. With climate change's mounting challenges, the sheep have become a focus of government-led breeding and conservation initiatives. However, there is a critical knowledge gap regarding the sheep's genetic information, including their origins, diversity, population structure, and genetics, as well as the morphological basis of their adaptive traits. This gap has hindered the development of breeding programs and genetic resource conservation efforts. In an effort to contribute to filling this knowledge gap, we employed a two-fold approach to investigate Phan Rang sheep's morphometrics and genetic lineages. First, we collected body conformational data to facilitate the quick identification of purebred individuals. Secondly, we collected and analyzed the mitochondrial DNA control region (D-loop) and the Y chromosome SRY and SRYM18 sequences to elucidate the maternal and paternal lineages of the sheep. Of the sheep analyzed for the D-loop, approximately one-third belonged to haplogroup A, while the remainder belonged to haplogroup B. For the paternal lineage, two main Y haplotypes, H5 and H6, were identified. Overall, the findings supported the hypothesis of dual origins for the Phan Rang sheep. The Phan Rang sheep, considered the sole indigenous breed of Vietnam, are primarily concentrated in the two central provinces of Ninh Thuan and Binh Thuan, with Ninh Thuan accounting for more than 90% of the country's sheep population. These provinces are known for their high temperatures and frequent droughts. The long-standing presence of the Phan Rang sheep in these regions suggests their potential resilience to heat stress—a trait of increasing interest in the face of global climate change. Despite the breed's significance, a critical knowledge gap hinders conservation and breeding programs. To address this, our study employed a two-pronged approach. First, we collected body conformational data to aid in breed identification. Second, we analyzed mitochondrial DNA (D-loop) and Y chromosome markers (SRY and SRYM18) to elucidate the maternal and paternal lineages. Among the 68 Phan Rang sheep analyzed for their D-loop, 19 belonged to mitochondrial haplogroup A, while 49 belonged to haplogroup B. The haplogroups can be subdivided into 16 unique haplotypes. All 19 rams surveyed for their paternal lineages belonged to haplotypes H5 and H6. These findings strongly support the hypothesis of dual origins for the Phan Rang sheep. This study presents the first genetic data for the Phan Rang breed, providing crucial insights for future research and conservation efforts. [ABSTRACT FROM AUTHOR]

The Quebec population is one of the rare populations of its size for which genealogical information is available for an uninterrupted period of almost four centuries. This allows for in-depth studies on the formation and evolution of a young founder population. Using data from two major population registers, in this study we focus on the maternal and paternal lineages (i.e., strictly female or male genealogical lines) that can be traced back within the Quebec genealogies. Through the analysis of these lineages it is possible to characterize the founders who transmitted to the contemporary population their mitochondrial (for females) and Y-chromosome (for males) DNA. The basic material consists of 2,221 ascending genealogies of subjects who married in the Quebec population between 1945 and 1965. On average, more than nine generations of ancestors were identified among the lineages. Analyses of maternal and paternal lineages show that the number of paternal founders is higher and their origins and genetic contributions are more variable than that of maternal founders, leading to a larger effective population size and greater diversity of Y chromosomes than of mtDNA. This is explained for the most part by differential migratory patterns among male and female founders of the Quebec population. Comparisons of sex-specific genetic contributions with total genetic contribution showed a strong correlation between the two values, with some discrepancies related to sex ratio differences among the founders' first descendants. [ABSTRACT FROM AUTHOR]