mtDNA polymorphisms in five French groups: importance of regional sampling

Area of Science:

• Population Genetics
• Human Migration Studies
• Mitochondrial DNA Analysis

Background:

• France exhibits regional heterogeneity based on classical markers.
• Mitochondrial DNA (mtDNA) is a valuable tool for tracing maternal lineage and population history.
• Previous studies suggest historical admixtures in French populations, particularly in Brittany.

Purpose of the Study:

• To test the homogeneity of the French mitochondrial gene pool.
• To analyze polymorphisms in D-Loop and coding regions of mtDNA in 210 individuals from five French regions.
• To evaluate the capacity of mtDNA to detect historically documented admixtures, specifically between British/Irish and Breton populations.

Main Methods:

• Analysis of D-Loop and coding regions polymorphisms in mitochondrial DNA.
• Careful selection of 210 individuals based on geographical origin and maternal pedigree.
• Statistical analyses of mtDNA diversity and structure within and between British, Irish, and French groups.

Main Results:

• mtDNA analysis revealed regional specificities in haplogroup distribution, indicative of successive settlements.
• Affinity was observed between the Morbihan region and Britain/Ireland.
• Genetic evidence supported an admixture event in Morbihan, consistent with historical migrations from Britain and Ireland into Brittany.
• Distinct genetic patterns were found between geographically adjacent regions (Morbihan and Finistère).

Conclusions:

• mtDNA analysis successfully identified a historically reported admixture event.
• The study highlights the significant influence of sampling procedures and representativeness in migration studies.
• Regional sampling is critical for understanding the spread and origin of European haplogroups like U5a1a and U8.