Costilow yDNA Results

Kenneth L. Costilow Jr. yDNA-67 haplogroup R-M269 (approx. 4,450 BCE), subclade of R-P297 (approx. 13,000 BCE)

• Exact match with Randolph Costilow.

• Genetic Distance of 3 Steps* with surnames: Kelly, Litton, Marlowe, McAdam, McGee/McGhee and Morrison.
  *Equating to a paternal-line connection somewhere between 1300-1850 CE.

• NO Costello matches of any variation.

Randolph M. Costilow Jr. yDNA-12 haplogroup R-M222 (approx. 150 BCE), subclade of R-Z2965 (approx. 1,600 BCE)

• Exact match with Kenneth Costilow.

• NO Costello matches of any variation.
  
  

Kenneth L. Costilow Jr. and Randolph M. Costilow Jr. are documented 3rd cousins, both descending from different sons of James Andrew J. Costilow and his first wife, Martha Ann Miller (Walter Lynn Costilow and Ceabron Callihan Costilow, respectively). The Costilow yDNA haplogroup would be R-M222, a refined and distant subclade of R-M269. R-M222 itself is a distinct subclade of the yDNA haplogroup R1b, most commonly observed in individuals of Irish and Scottish ancestry—especially those from Northwestern Ireland and the Lowlands of Scotland. This lineage is marked by the M222 SNP (Single Nucleotide Polymorphism) and is often linked to the paternal heritage of people from these areas. R1b is one of the most common Y-chromosome haplogroups in Europe and M222 marker is a genetic mutation that identifies individuals who share a common paternal ancestor who lived roughly 1,600 years ago.

Former research has R-M222 associated with the legendary Irish High King, Niall of the Nine Hostages, who is thought to have lived during the 5th century. Research indicates that a notable proportion of Irish men carrying the M222 marker may trace their direct paternal lineage back to him. The widespread presence of haplogroup R-M222 in northern Ireland and parts of Scotland is likely tied to influential figures such as Niall of the Nine Hostages. Though shrouded in legend, Niall is believed to have been a King of Tara, a ceremonial seat of power in northwestern Ireland, during the late 4th century C.E. His name originates from tales in which he held nine hostages from rival territories to secure dominance. While many of the stories surrounding Niall were likely written centuries after his death and may be more myth than fact, genetic research supports the idea that the Uí Néill dynasty—whose name means “descendants of Niall”—does trace back to a single male ancestor who likely belonged to haplogroup R-M222, a branch of R-M269.

However, it almost certainly wasn’t Niall himself, as the individual associated with the R-M222 lineage lived thousands of years before Niall’s reign; so they could not have been the same person. That said, the genetic lineage appears strongly connected to the Dál Cuinn/Uí Néill dynasty, to which Niall belonged, making it likely that Niall was a descendant of this earlier ancestor.

Reviewing Kenneth and Randolph's yDNA Ancestral Origins, available at FamilyTreeDNA, shows they match heavily with others who have tested from Ireland, Scotland and England:

Kenneth Costilow Randolph Costilow

12 Markers Exact Matches:

• Ireland: 7.9%

• Scotland: 1.9%

• England: 1.5%

25 Markers Exact Matches: 25 Markers Genetic Distance -1:

• Ireland: 0.1% Ireland: 2.7%

• Scotland: 0.1% Scotland: 0.7%

• England: 0.1% England: 0.3%

37 Markers Genetic Distance -2:

• Ireland: 0.1%

• Scotland: 0.1%

67 Markers Genetic Distance -3:

• Ireland: 0.1%