What is a Haplogroup in Genetics


What is a haplogroup, cause i see it alot on 23andme things

In: 6

A large group of genetic characteristics inherited from an ancient group. These generally correlate X and Y (if you have each), so you’ll have a maternal haplogroup and a paternal haplogroup. This’ll be the last major divergence your DNA came from, pointing where your ancestors came from 1000’s of years ago.

**At a DNA level you have alleles:**

An allele is the basepair at one loci.

Person A may have Chr1:Pos100 = AA

Person B may have Chr1:Pos100 = AA

Person C may have Chr1:Pos100 = AG

Person A and Person B share the same alleles at that basepair. Person C only shares one allele with the others.


**At a higher level, you have a haplotype:**

A haplotype is the alleles across multiple loci.

Person A may have Chr1:Pos100-101 = AA TT

Person B may have Chr1:Pos100-101 = AA GG

Person C may have Chr1:Pos100-101 = AG GG

Now Person A is the odd man out. Person B and Person C share the same haplotype on one of Peraon C’s chromosomes.


**Go up to an even higher level, you have haplogroups:**

Mitochondrial DNA (mtDNA) comes only from the mother.

Person A has mtDNA = ATAT

Person B has mtDNA = TTTA

Person C has mtDNA = ATAT

Now Person B is the one left out, because Person A and Person C share the same maternal lineage.


**So although A=B at some allele, and B=C at some haplotype, A and C share the same haplogroup.**