Geographic distribution of consanguinity in Europe

Area of Science:

• Human genetics
• Population genetics
• Anthropology

Background:

• Consanguinity, the degree of ancestry between related individuals, varies significantly across populations.
• Understanding factors influencing consanguinity is crucial for population genetics and estimating allele frequencies.

Purpose of the Study:

• To investigate the relationship between average consanguinity and geographic factors across diverse populations.
• To explore the influence of population size and cultural-historical context on consanguinity patterns.

Main Methods:

• Analysis of consanguinity data from 20 large regional/national samples (Roman Catholic Dispensations, state archives).
• Statistical analysis including two-way and one-way ANOVA to assess the significance of population size and geographic divisions.
• Comparison of patterns in mainstream populations versus isolates.

Main Results:

• A significant negative correlation was found between average consanguinity and latitude (r = -0.738), attributed to cultural-historical factors.
• Mainstream populations showed significant geographic differences in consanguinity, unlike isolates.
• Population size was a significant factor, but geography was not significant in two-way ANOVA for mainstream samples.

Conclusions:

• Consanguinity patterns are strongly influenced by cultural-historical factors and latitude, not solely by geographic proximity.
• Population size significantly impacts consanguinity levels, while geographic divisions show less influence in larger samples.
• Observed consanguinity patterns may affect the accuracy of frequency estimates for rare alleles and genetic disorders.