A Chinese got 0.1 Somali trace ancestry on 23andMe. Even at 90% confidence level the 0.1% Somali still shows in his ancestry. He claims that his 0.1% is in Choromosome 6 which is a strong indicator that he had a somali ancestry in his family tree. I asked Chatgpt for more info on Choromosome 6 and here is what it said:-
"Yes, chromosome 6 can retain ancestry information in your DNA—and in fact, it's one of the most important chromosomes for ancestry and population genetics studies. Here's why:
Why Chromosome 6 Is Special for Ancestry
Home of the HLA Region (MHC)
The HLA region (Human Leukocyte Antigen), also called the MHC (Major Histocompatibility Complex), is located on chromosome 6.
This region is highly variable between populations and individuals, making it an excellent marker for ancestry, especially recent admixture and population-specific immune adaptations.
Strong Signals of Natural Selection
Because the MHC plays a central role in immune response, it evolves rapidly under environmental pressures (e.g., infectious diseases).
Different populations have developed distinct HLA profiles, which can reflect local adaptation and deep ancestry.
Used in Forensic and Medical Genetics
Chromosome 6 (especially the HLA genes) is used in:
Bone marrow and organ donor matching
Forensic population studies
Tracing historical admixture, such as identifying African, Eurasian, or Indigenous American components in populations.
Ancestry May Be Retained Longer
Because of balancing selection (natural selection that maintains multiple variants), some ancestral alleles in this region persist longer than in other parts of the genome. That means:
You might retain deep ancestral signals on chromosome 6 that aren’t as visible elsewhere in your DNA.
Caveats
While chromosome 6 can retain ancestry, ancestry testing companies often mask or downweight the HLA/MHC region due to its complexity and high variability.
The region can show high linkage disequilibrium (genetic variants inherited together), which may make interpretation tricky.
Summary
FeatureChromosome 6 Role
Immune system genesHosts HLA/MHC
High variabilityYes
Good for ancestry analysis?Yes, especially for immune traits and selection
Used in medical matching?Yes
Interpretation difficultyHigh (complex region)"
Anyone who has traces can now check if it's in Choromosome 6 for legitimacy purposes.
"Yes, chromosome 6 can retain ancestry information in your DNA—and in fact, it's one of the most important chromosomes for ancestry and population genetics studies. Here's why:
Why Chromosome 6 Is Special for AncestryHome of the HLA Region (MHC)
The HLA region (Human Leukocyte Antigen), also called the MHC (Major Histocompatibility Complex), is located on chromosome 6.
This region is highly variable between populations and individuals, making it an excellent marker for ancestry, especially recent admixture and population-specific immune adaptations.
Strong Signals of Natural Selection
Because the MHC plays a central role in immune response, it evolves rapidly under environmental pressures (e.g., infectious diseases).
Different populations have developed distinct HLA profiles, which can reflect local adaptation and deep ancestry.
Used in Forensic and Medical Genetics
Chromosome 6 (especially the HLA genes) is used in:
Bone marrow and organ donor matching
Forensic population studies
Tracing historical admixture, such as identifying African, Eurasian, or Indigenous American components in populations.
Ancestry May Be Retained Longer
Because of balancing selection (natural selection that maintains multiple variants), some ancestral alleles in this region persist longer than in other parts of the genome. That means:
You might retain deep ancestral signals on chromosome 6 that aren’t as visible elsewhere in your DNA.
CaveatsWhile chromosome 6 can retain ancestry, ancestry testing companies often mask or downweight the HLA/MHC region due to its complexity and high variability.
The region can show high linkage disequilibrium (genetic variants inherited together), which may make interpretation tricky.
SummaryFeatureChromosome 6 Role
Immune system genesHosts HLA/MHC
High variabilityYes
Good for ancestry analysis?Yes, especially for immune traits and selection
Used in medical matching?Yes
Interpretation difficultyHigh (complex region)"
Anyone who has traces can now check if it's in Choromosome 6 for legitimacy purposes.
