The aim of this dissertation was to address gaps in our understanding of the human genetic histories at the northern and eastern peripheries of the Himalayan arc. Despite occupying an integral location in a challenging high-altitude environment between lowland East Asia, Southeast Asia, and the Tibetan Plateau at its eastern periphery and between Central Asia, South Asia, and the Tibetan Plateau at the northern periphery, these regions are severely understudied both archaeological and genetically, leading to a dearth of knowledge about the early occupants and their genetic relationship with present-day inhabitants in and around the region. The two chapters in this thesis illustrate complex, heterogeneous genetic interactions in the past at the crossroads of South and Central Asia on the one hand, and East and South Asia on the other.