A haplogroup is a genetic population group that shares a common ancestor on the maternal or paternal line. It is identified through specific genetic markers in DNA, which can be passed down through generations. Haplogroups help researchers trace human migration patterns and understand the genetic diversity of populations. Haplogroups are often denoted by letters and numbers, such as Haplogroup R or Haplogroup L. They are used in fields like anthropology, genealogy, and genetics to study human history and relationships. By analyzing haplogroups, scientists can gain insights into the ancestry and evolution of different human populations.