Final answer:
MtDNA sequencing and haplogroup establishment allowed researchers to analyze genetic ancestry and relationships in the Hoyo Negro project, providing insights into human evolution.
Step-by-step explanation:
The use of mtDNA sequencing and the establishment of haplogroups allowed researchers working on the Hoyo Negro project to establish the genetic ancestry and relationships among individuals found in that cave system. By analyzing the variations in mitochondrial DNA, scientists were able to track the maternal lineages and identify different haplogroups, which represent branches on the human phylogenetic tree. This information provided insights into the origins and migrations of ancient populations and contributed to our understanding of human evolution.