Finger ridge-count variability in sub-Saharan Africa

Area of Science:

• Anthropology
• Population Genetics
• Dermatoglyphics

Background:

• Finger ridge-counts are a heritable trait used in population studies.
• Previous analyses often focused on total ridge-count, potentially overlooking finer variations.

Purpose of the Study:

• To investigate geographical patterns in finger ridge-counts across sub-Saharan African populations.
• To determine if specific ridge-count contrasts, rather than total counts, correlate with population genetics and gene flow.

Main Methods:

• Multiple regression analysis using 10 finger ridge-counts and total ridge-count against latitude and longitude.
• Principal components analysis to identify within-group variations.
• Comparison of findings with known patterns of gene flow based on serological genes.

Main Results:

• Geographically patterned variation in ridge-counts is primarily due to contrasts between specific digit groups (e.g., digits 4&5 vs. 2&3).
• South/south-east African populations show low contrasts, West Africans high contrasts, and South-West Africans intermediate.
• These contrast patterns align well with established gene flow models in Africa.

Conclusions:

• Finger ridge-counts are valuable for population studies, but their multicomponent nature must be considered.
• Focusing on specific digit contrasts provides a more accurate reflection of population structure and history than total ridge-count alone.