Carolyn:
Haplogroups are defined by genetic researchers. All men past and
present(and women - defined by their mtDNA) are a specific haplogroup. Each
haplogroup has one or more mutations specific to their haplogroup only.
These mutations occurred from 10,000 to 50,000 years ago. So every man with
a specific mutation is in a separate haplogroup. Every man in a separate
haplogroup is related within the timeframe of 10 to 15 thousand years.
Mutations that occur more recently are what are tested for in our project.
That is why it is possible to be in the same Haplogroup and not have a
recent genetic match.
This link may help:
https://www3.nationalgeographic.com/genographic/glossary.html
"Haplogroup
Branches on the tree of early human migrations and genetic evolution.
Haplogroups are defined by genetic mutations or "markers" found in Y
chromosome and mtDNA testing. These markers link the members of a haplogroup
back to the marker's first appearance in the group's most recent common
ancestor. Haplogroups often have a geographic relation.
Haplotype
A person's individual footprint of all tested genetic markers. Even the
difference of a single genetic marker delineates a distinct haplotype. "
There are maps at the website to see the "Journey of Man" also that may help
you picture it.
Hope this helps.
Vickie