The Western Atlantic Modal Haplotype is the most common Y-DNA signature of Europe’s most common Haplogroup, R1b. Simply put your ancestors have experienced a dramatic population explosion over the past 10,000 years, probably since the end of the Last Glacial Maximum (LGM-that’s Anthropology-speak for the last Ice Age) that covered most of Europe beginning 20,000 years ago and lasting for 10,000 long cold winters.
R1b, and its most common Haplotype (yours), exists in high or very high frequencies in all of Western Europe from Spain in the south to the British Isles and western Scandinavia in the north. It appears that approximately 2.5% in Western European males share this most common genetic 12 marker signature and because of its very high frequency we always suggest that for genealogy purposes people in this group should only use our 25 or 37 marker test for their genealogy.
Anthropologists have been describing for many years that only a select % of all the males in past societies did the vast majority of fathering, while other males lost the opportunity to pass on their Y-Chromosomal genes.
On a lighter note it’s clear that R1b’s Western Atlantic Modal Haplotype has contributed much more than its ‘fair share’ in populating Western Europe.
Haplogroup R1b1c is the most common haplogroup in European populations. It is believed to have expanded throughout Europe as humans re-colonized after the last glacial maximum 10-12 thousand years ago. This lineage is also the haplogroup containing the Atlantic modal haplotype.
Specific mitochondrial haplogroups are typically found in different regions of the world, and this is due to unique population histories. In the process of spreading around the world, many populations—with their special mitochondrial haplogroups—became isolated, and specific haplogroups concentrated in geographic regions. Today, we have identified certain haplogroups that originated in Africa, Europe, Asia, the islands of the Pacific, the Americas, and even particular ethnic groups. Of course, haplogroups that are specific to one region are sometimes found in another, but this is due to recent migration.
The mitochondrial super-haplogroup U encompasses haplogroups U1-U7 and haplogroup K. Haplogroup U5, with its own multiple lineages nested within, is the oldest European-specific haplogroup, and its origin dates to approximately 50,000 years ago. Most likely arising in the Near East, and spreading into Europe in a very early expansion, the presence of haplogroup U5 in Europe pre-dates the expansion of agriculture in Europe. Haplogroup U5a1a—a lineage within haplogroup U5—arose in Europe less than 20,000 years ago, and is mainly found in northwest and north-central Europe. The modern distribution of haplogroup U5a1a suggests that individuals bearing this haplogroup were part of the populations that had tracked the retreat of ice sheets from Europe.