Around 7,000 years ago, an observable genetic bottleneck suggests a male-female ratio equivalent to approximately 1 man for every 17 women in terms of reproductive success and genetic contribution.
This significant disparity, primarily reflected in genetic diversity, emerged during the Neolithic period and lasted for about 2,000 years, affecting populations across Africa, Europe, and Asia. Researchers discovered a dramatic collapse in the genetic diversity of the Y chromosome, which is passed down exclusively through the male lineage. This collapse indicates that far fewer men contributed to the gene pool of subsequent generations compared to women.
Understanding the Neolithic Genetic Bottleneck
The phenomenon, often referred to as the "Neolithic Y-chromosome bottleneck," implies that while the overall population might not have literally had only one male for every 17 females alive, the effective breeding population of males was severely limited. This means that a relatively small number of men were responsible for fathering the majority of offspring, leading to a drastic reduction in male genetic diversity over time.
Key Aspects of the Ratio:
- Timeframe: Approximately 7,000 years ago, extending over a 2,000-year period.
- Geographical Spread: Observed across Africa, Europe, and Asia.
- Nature of the Ratio: Not a direct census count of individuals at one point, but a reflection of a bottleneck in genetic diversity and reproductive success, specifically concerning the Y chromosome.
- Implied Impact: Suggests a period where a very small number of men had disproportionate reproductive success, while many others did not pass on their Y-chromosomes.
Male-Female Ratio (Genetic Contribution)
| Category | Value |
|---|---|
| Effective Male Count | 1 |
| Effective Female Count | 17 |
| Ratio (Male:Female) | 1:17 |
This genetic event points to complex social dynamics, environmental pressures, or conflicts that significantly impacted male lineages during this ancient period. For further details on this fascinating discovery, more information is available Something Weird Happened to Men 7000 Years Ago, And ... - ScienceAlert.
