Definitions 🧵:
A #haplogroup is a combination of #alleles that tend to be inherited together.
An #allele is a variation of the same sequence of nucleotides at the same place on a DNA molecule.

#Haplogroups pertain to a single line of descent. As such, individual membership of a haplogroup relies on a small proportion of the #genetic material possessed by that individual.

Mothers pass on mitochondrial #DNA unmixed to all their children; so the #ancestry can be traced along the maternal line.