SOURCES OF DIFFERENT CASEY GENETIC LINES

According "The Internet Surname Database," the Gaelic name "O'Cathasaigh" (original source of the Casey surname) was a clan-based surname. Like most Irish surnames, it was "taken from the heads of tribes, revered elders or from some illustrious warrior." This web-site states that "six distinct septs of this name existed in Ireland. The most important of these in early times were the erenaghs of Devenish, County Fermanagh, where the family held church property from generation to generation. A minor sept, having the prefix "Mac" instead of "O," was located in County Monaghan and three bishops named MacCasey occupied the see of Clogher in the 14th century. Another leading O'Casey family were Lords of the Suaithni (comprising the modern barony of Balrothery West, County Dublin) and a further family were erenaghs of Clondara in the baroney of Athlone, County Roscommon. The Dalcassian septs were seated at Liscannon, County Limerick and near Mitchelstown, County Cork, the name is now most numerous in these Munster counties. The first recorded spelling of the family name is shown to be that of Johane Casey, which was dated April 18, 1569, marriage to Thomas Nowell, at St. Gregory by St. Paul's, London.

Surnames became necessary when governments introduced personal taxation. In England, this was known as "Poll Tax." Polyphyletic surnames are surnames that have multiple unrelated men first using the surname around 600 years ago when most Irish men first started using surnames. Surnames based on trade are polyphyletic such as Smith, Baker, Farmer, Cooper and many others. These kinds of surnames will obviously have many genetic origins. Surnames based on local topography are also another common source of polyphyletic names such as Hill, Meadows, Lake, Brooks, Rivers and many others. Another variation of polyphyletic surnames are clan based names such as Casey. These surnames just have few genetic sources as they were limited to leaders of clans. As stated above, there are believed to be six clan leaders that first used the Casey surname (its earlier derivatives). DNA tends to support a very limited number of genetic origins which is consistent with the name being taken by six clan leaders. It does not appear that the Casey name is a more typical polyphyletic name where dozens or hundreds unrelated men used a surname based on common trades or topographic terms. Surnames with one genetic origin are known as monophyletic names. The Casey surname appears to have more the traits of a monophyletic surname with most genetic variation introduced via NPE births.

There are currently at least seven clusters of Casey DNA submissions that have enough DNA variation to imply that these seven clusters can not share a common ancestor in the genealogical time frame (200 or 300 years). First, there are two dominant clusters (SC and Munster) that represent over half of the DNA submissions (and these two clusters may be related in the distant past – 400 to 600 years ago). There are also two smaller clusters with radically different DNA (haplogroups E1b1 and J2). Due to the size of these small clusters and the haplogroups having non-Irish origins, these two clusters are probably due to NPE births in the distant past. Finally, there is the large grouping of R1b1a2 submissions that include many submissions that are not that closely related and could eventually represent at least three additional clusters once more submissions are available. So there are at least seven possible clusters in the Casey surname project to date with a mere 50 submissions.

Until the availability of DNA submissions to analyze, I had very inaccurate assumptions concerning the exact relationship of my Casey lines to other Casey lines. First, I incorrectly assumed that almost all Casey lines probably shared a common ancestor and shared common DNA as well. I never really thought about how over 25 generations there could be several NPE births that created genetically different Casey lines. Second, I really never considered that multiple unrelated men may used the Casey surname when our Irish ancestors started using surnames around 600 years ago. Due to information obtained from current DNA submissions, I see no reason to doubt that the Casey surname has six genetic origins when these clan leaders first used the Casey surname.

I also naively assumed that my ancestors had high fidelity transmission of surnames (where DNA tracks the surname). High fidelity DNA transmission is like a CD music disc where there is very little noise (deviation of sound). The DNA of our Casey ancestors are more like vinyl records with a few scratches that result in some noise. With transmission of DNA handed down by our male Casey ancestors, NPE births has probably created several distortions of DNA tracking surnames. With only around 50 submissions to date, there are at least seven genetically different clusters of Casey submissions. This is significantly less genetic variation than most DNA surname studies – especially for surname that is as common as the Casey surname. With only around 50 submissions to date, it is obvious that very few unrelated men first took on the Casey surname. There are only three possibilities:

1) The historical version that six clan leaders were the only six unrelated men that first used the surname (most probable for most genetic Casey lines).
2) There may be only one man with the surname and all others genetic lines are early NPE births (since there are so few genetic origins, this has some possibility of being true).
3) There may be some combination of the first two scenarios (this is by far the most likely scenario as two non-Irish deep ancestries imply this).

In the book, "American Surnames," by Elsdon C. Smith, 1969, the top 2,000 surnames were compiled using the 1964 Social Security database. It stated that the Casey surname was the 396th most common surname in the United States and that 63,100 individuals had the surname of Casey. Since military, state government employees and many young children are missing from the 1964 database, these numbers would be around 20 percent more than shown. The web site by the United States Census Bureau compiled 88,000 surnames from the 1990 census. It shows that the Casey surname was the 479th most common surname and represents 60,000 individuals. The 1990 census was based on a small sampling of the entire population but adjusted for the entire population. This partial census intentionally selected many more samples for some minorities (primarily Hispanic and Asian). Therefore, the number and ranking for most surnames are much less than actual. There are probably around 75,000 Casey individuals in the United States today and the Casey surname is probably around the 450th most common name today. With 75,000 living individuals with the Casey surname, it reasonable to believe that there should be several NPE births that could be the source of genetic variations found with the Casey surname over the last 600 years (time frame when surnames were first used by our Irish ancestors).

Since several early NPE births are probably present, I now believe that all the people with the Casey surname could descend from one individual or up to six individuals as the historical evidence suggests. It is very likely that NPE births will be the primary source of most of the genetic variations that will found with the Casey surname. This also means that the Casey surname has monophyletic surname characteristics (a surname that originates from one male ancestor). The Casey surname is definitely not the typical polyphyletic surname having dozens or hundreds of genetic sources of the surname. The Casey surname is fairly common surname and I believe that there is not enough genetic variation found with current DNA submissions to support the numerous multiple unrelated men taking the surname of Casey 600 years ago. Of course, there could be a few unrelated men that first used the Casey surname – but the majority of the genetic variations of the Casey surname will eventually be more likely originate from NPE births.

ORIGINS OF THE CASEY SURNAME

The surname Casey originated from the Gaelic name "O'Cathasaigh." The date that our ancestors first used surnames is extremely important in understanding how many genetic origins exist. "The Internet Surname Database" supports that Casey was a typical surname that originated around 600 years ago while other sources suggest as much as 1,000 years ago. After the Anglo-Norman invasion, the name was "anglicized" to O'Casey and by the 1300's it was further "anglicized" to its present form of Casey. After the introduction of surnames, life was still very brutal with constant warfare between neighboring clans and neighboring nations. These conflicts left orphan sons who adopted and raised by others on both sides. Other clan members would regularly adopt the young sons of fallen comrades and these sons may have taken on new surnames if they were very young. Also, there was many orphans left because of widespread outbreaks of diseases and food shortages. The potato blight outbreaks caused severe food shortages and starvation for many Irish families. In these turbulent times, wars, diseases and accidents resulted in the need to adopt orphaned sons and probably introduced many DNA varieties to the Casey surname.

With recent trends for a major increase of out-of-wedlock births, the rate of NPE births will be greatly increase in the future. The age of most Irish surnames is around 600 years ago. Other sources suggest that the origin of the Casey surname was 1,000 years ago. The age of the surname could make a significant difference on how many clusters are due to NPE births vs. random genetic drift over many generations. This Surname Study assumes 600 years when attempting to define a genetic cluster of related Casey lines and assumes 300 years for a genealogical cluster. Having an older origin of any surname would be significant as this older time frame would reduce the number of genetic clusters. By assuming the "1,000 year" definition of the genetic cluster, the "600 year" definition of genetic clusters could result in merging of several genetic clusters by allowing more time for genetic drift (random mutations). This could have a profound effect on determining the major branches of each Casey line of today and could radically change the definition of the DNA of our "Most Common Recent Ancestor."

I never considered any genealogical importance of the age of the surname. With DNA information supplementing traditional research, the age of the surname could influence how we have to connect our lines together. The older the surname, the fewer NPE births are required to justify the genetic variation of the Casey surname. As the age of the surname get older, random genetic drift over many more generations would become a more common source of the genetic variations of the Casey surname. Some of the R1b1a2 genetic clusters could merge together. The exact age of the surname needs to investigated further to properly analyze how many unrelated lines of genetic sources is supported by DNA evidence.

SURNAME VARIATIONS

There are several spelling variations of the surname Casey. The 1990 US Census shows the following:

The known spelling variations for the Casey surname are more rare than for other surnames. Researchers of these surname variations have an opportunity to verify that the spelling variations are related to the Casey surname via DNA submissions. These spelling variations could be linked to specific clusters of established genealogical Casey clusters. To our knowledge, none of these spelling variations have been tested to date. The 1990 census did not find any entries for other suspected variations of the Casey surname. These variations include Cazey, Cazy, Cacey, Caesey, Caesy, Casee, Casie, Casye, Ceasy, Ceasey, Kacey, Kasy, Kazey, O'Casey, McCasey, MacCasey, Cathasaigh O'Cathasaigh, McCathasaigh and McCathasaigh. It is assumed that any early documentation of these surnames were due to spelling errors or that these earlier variations did not result in the creation of surname variation that still survives today. There are other surnames where the could be cross-over between similar spellings:

Case 813th
Kase 31,754th
Caskey 4,192nd
McCaskey 22,082nd
Kaskey 62,943rd
Kasky 83,113th
Cassidy 1,505th
Cassady 6,189th
Cassity 8,665th
Casssiday 58,085th

There are currently no known proven connections between the Casey surname and these possible crossover surnames. A researcher of the Case family has joined the Casey surname project (the reasons are unknown for this person joining the Casey surname project). Researchers of these crossover surnames should look at the DNA reviews of Casey clusters looking for common DNA marker values and common genealogical evidence putting these families in the same geographical areas.

GEOGRAPHIC ORIGIN OF THE CASEY SURNAME

There is little surprise that the Casey surname has Irish origins. However, DNA evidence clearly supports this assumption. The Irish Haplogroup R1b1a2 dominates the DNA submissions of the Casey Surname Project and also supports that the genes of our Casey ancestors originated from Ireland. There is also little surprise that the country of origin for all submissions outside of the United States has been exclusively Ireland as well. The largest new discovery from DNA submissions is where these Casey lines originated in Ireland. A lot of the South Carolina Casey researchers have long believed that our Casey lines originated from County Tyrone in the northern part of Ireland. This still may be true as it only takes one early Casey family moving to the northern part of Ireland to establish this geographic tie. This County Tyrone connection is based on a Casey manuscript in 1876 claim that the dominant line in the United States came from the northern part of Ireland (County Tyrone).

To our surprise (at least the South Carolina cluster), almost all Casey DNA submissions that trace their ancestry back to Ireland do not have ties to any northern counties in Ireland. Almost all have connections to southwest Ireland: Clare (2), Cork (2), Kerry (2) and Limerick (2). However, one recent DNA submission shows its origin as County Managhan, which is much further north and east of all other Casey submissions. The historical sources for the Casey surname also state that a sept of the Casey surname originates from County Managhan. Unfortunately, there are currently no DNA submissions with the South Carolina DNA fingerprint that have origins in Ireland (but keep our fingers crossed for genetic evidence breaking that brick wall some day). With the United States, Australia and Canada being on the receiving end of immigration the vast majority of the time (vs. early immigration to Ireland), the E1b1 and J2 clusters probably originated via NPE births in the United States. However, there is still a remote chance that this cluster could have origins in Ireland as well (not all Irish people have deep ancestry tied to Ireland).

The DNA submissions in this Surname Project are dominated by submissions that currently reside in the United States and probably does not represent a random sample of international submissions with the surname of Casey. At present, four submissions that originated from southwest Ireland migrated to various northern states in the United States. Unfortunately, the present day location of the four other submissions with ties to early Ireland is not known. This is why it is very important to contact the Casey admins and provide this critical information to the Casey DNA Project. Due to incomplete information on these lines, it is more difficult to determine the bias of the existing submissions of Casey surname. Due to the lack of documentation, we have to make the assumption that these four other lines with origins in Ireland have recent ancestors in the United States. We must conclude that since all documented lines to present day are representative to all submissions with early ties to Ireland. Therefore, the Casey Surname Study does have extreme bias towards submissions with recent ties to the United States.

Since the current submissions have no documented current residences in Ireland, this makes any speculation concerning the possible early origins of Casey lines more challenging and less accurate. From a statistical point of view, we must have more submissions with current residences in Ireland (as well as United Kingdom, Australia, Canada and other countries) in order to speculate the place(s) of origin of the Casey surname. Unfortunately, most DNA surname projects have this bias of United States submissions and this bias leads to less accurate and less complete information about our origins from Ireland. This bias not only reduces our ability to determine where our Casey lines came from in Ireland – but also limits our ability to determine the DNA markers of our early ancestors and reduces our ability to accurately predict branches of our DNA descendancy charts. We need to raise funds and recruit Casey submissions from current day Ireland and other countries. Otherwise, we introduce bias to our selection of DNA submissions. From a statistical point of view, any bias (deviation from random selection) always leads to less accurate analysis of the information.

GEOGRAPHIC DISTRIBUTION OF THE CASEY SURNAME

People with Irish ancestry are much more common in former British related countries outside of Ireland than are residing in Ireland today. It is amazing how the Irish people have spread across the globe in such large quantities. People with Irish ancestries are found across the world:

1) 45.5 million in the United States
2) 7.2 million in Australia and New Zealand
3) 6.9 million in the United Kingdom (including northern Ireland)
4) 5.2 million in the Republic of Ireland
5) 4.3 million in Canada
6) 800 thousand in Latin America (primarily Mexico and Argentina)
7) 100 thousand in other western European countries (primarily France and Germany)

Genealogical records from the middle 1800s support that the Casey surname tracks this world-wide distribution of the Irish people:

1) 3,318 Casey heads of households in the 1860 census of the United States
2) 2,327 Casey households in the property surveys of Ireland (1847 to 1864)
3) 1,273 Casey heads of household in the 1841 census of the United Kingdom
4) 4,789 Casey individuals in present day Australia (early online records are not available)

These sources show that the southwestern part of Ireland (Munster) dominate the distribution of Casey households with 1,157 households (50 %): Cork (362), Limerick (273), Kerry (249), Tipperary (175) and Waterford (98). In the United Kingdom, London (410) and Lancashire County (224) include half of all of the Casey households. In the United States, the northeastern states dominate the 1860 census (49 %): New York (773), Massachusetts (329), Pennsylvania (223), Connecticut (97), New Jersey (66), Maine (54), Vermont (42) and Rhode Island (41). Midwestern states are the second largest concentration of Casey households (33%): Illinois (234), Missouri (165), Ohio (223), Kentucky (114), Wisconsin (98), Michigan (75), Indiana (70), Iowa (61) and Minnesota (41). Southern states (which dominate the Casey DNA Surname Project) have a very small representation (16%): Louisiana (73), Virginia (71), Tennessee (65), Arkansas (60), Alabama (46), Maryland (43), North Carolina (42), Georgia (40), South Carolina (39), Mississippi (31), Texas (28) and Florida (5).

With the above distributions, the current submissions of the Casey DNA studies are very biased with submissions from the United States and even more biased with submissions with DNA submissions that have ties to South Carolina (many descendants of these lines also resided in Illinois, Missouri and California). Currently, there is only one submission that reside in Australia and New Zealand (the second most popular residence for people with Irish ancestry). There are no known submissions that currently reside in the United Kingdom (the third most popular country with Irish ancestors). There are no known submissions that currently reside in Ireland (although many have known ties to earlier Ireland). There are no known submissions that currently reside in Canada (the fifth most popular country for people with Irish ancestry). The current submissions are heavily biased with submissions in the United States (as it should be due to most people with Irish ancestry reside in the United States). However, the lack of representation of other major countries where Casey families resided introduces bias into this study. Additionally, the origin of the surname of Casey is definitely is Ireland. With poor representation of Casey families currently residing in present day Ireland, the Casey Surname Study will be hard pressed to determine the geographic origin of the Casey surname due to this bias.