Sunday, 8 August 2021

A new branch downstream of I-Y33767 defined by BZ4354

Recently, a Big Y-700 test has been completed for Clements B742594. This is the fifth set of next generation sequencing (NGS) results we now have for men on the English arm of the I-Y33765 clade; the previous tests are two Big Y-500 tests (Clement 236748 & 282009) and two Big Y-700 tests (Clement 236748 & IN82043).

Before the completion of the latest analysis, genetic testing has established that the English arm divides into several lineages downstream from I-Y33767, possibly at some time during the later decades of the sixteenth century.  Further, using the documented genealogies of the five men known to be derived (+) for Y33765 it seems probable this divergence happened between Clement/s male lines that were living in the valley of the River Chew, North Somerset. 

As I discussed in my June blog, a comparison of 111STR results for Clements B742594 and three Clement men (236748, 282009 & IN82043) gave a hint, based on repeat values at two markers DYS481 and DYS717, that he was more closely related to Clement 236748 & Clement 282009.  All three men share a 26 repeat motif at DYS481and they also have a 19 repeat motif at DYS717.  In contrast, Clement IN82043 has 25 repeats at DYS481 and 20 repeats at DYS717. So, using these STR comparisons, in the June update I speculated that downstream from I-Y33767 the English branch divided, with Clement 236748 & 282009 with Clements B742594 in one group and Clement IN82043 in the other.  As we will see my speculation was correct about there being a branch below I-Y33765 but entirely wrong about the way in which these four men are related.

This error became clear immediately we had the complete Clements B742594 Big Y-700 result.  This shows that Mr Clements is ancestral for three SNPs for which each of the Clement men (236748, 282009 & IN82043) are derived.  These mutations are BZ4354, FT314945 & FT324244 and we can now see that they divide the Chew Valley Clement/s into two distinct branches downstream of I-Y33767.  Hence, because of these definitive "next generation sequencing" (NGS) data from Mr Clements Big Y test we can reject my mistaken conclusions based on STR comparisons and instead be confident of this division defined by the BZ4354 SNP.  This relationship is illustrated in our new I-Y33765 chart shown below.

Rather than removing the previous blog (June, 2021) that contains my incorrect assessment based on the STR comparisons, it seems to me that, together with this update, it illustrates the pitfalls of relying solely on STR markers and once more demonstrates that only SNP mutations provide a "gold standard" genetic assay for genealogy. 



Click on image to enlarge

Monday, 21 June 2021

I-Y33765 draft tree showing Short Tandem Repeat (STR) marker mutations, June 18th 2021

Previously, the charts I have drawn to illustrate our developing understanding of phylogeny for the I-Y33765 clade have been based on Single Nucleotide Polymorphism (SNPs) results from FTDNA Big Y-700 next generation testing.  In this draft however I have sketched a tree which shows  the estimated positions of Short Tandem Repeat (STR) marker mutations downstream from Y33765.  My interpretation is based on comparison of the results of eight men who have each tested 111 STR markers at FTDNA.  

Those mutations shown in blue type on the chart are "back" mutations in which the number of repeat motifs at that marker has been reduced compared to the upstream value shown in black, while "forward" mutations, in which the number of repeat motifs has increased, are shown with red characters.  The chart demonstrates how STR markers mutate randomly over time with both "forward" and "back" mutations happening at an apparently similar frequency on each of the lineages within our clade.

Most of the observed mutations are, as might be expected, in the fastest mutating STR markers but four of these changes have occurred in markers with the slowest rate of mutation.  All these slow marker mutations have occurred at some point during the last ten to fifteen generations, so within the conventional genealogical time-frame.  One of the English lineages, Clement IN82043, at marker DYS717 shows an increase from 19 to 20 repeats.  On the Swedish arm of the clade, Eklund IN78306 has a "forward" mutation from 18 to 19 repeats at DYS587 and a "back" mutation from 14 to 13 repeats at DYS497.  Lastly the Swedish, Jacobsson IN70815 lineage has a "back" mutation from 12 to 11 repeats at marker DY568.  Again, we can interpret these changes as demonstrating the completely random nature of alterations in Y-chromosome STRs. 

The most significant relational change in this latest version of the I-Y33765 tree concerns the expansion of the English branch downstream from I-Y33767.  Comparison of the 111STR results for Clements B742594 (in previous iterations of the I-Y33765 tree shown as YS32054) with those for the other English men has shown that he is most closely related to Clement 236748 and Clement 282009.  This finding prompted a reconsideration of the known documented genealogies for these three men and, as a result of this, a putative connection has been found between them with their most recent common ancestor (MRCA), George Clement, who was baptized at St Mary the Virgin, Compton Dando, Somerset, 1st December, 1678.  This finding would seem to indicate that the genealogies of all the presently known instances of I-Y33765 in England can now be shown to originate from an area of north-east Somerset close to the parish of Clutton.  Previously the earliest known Clement ancestry for 236748 and 282009 was in south Gloucestershire.  

Regular readers will recall that I have several times discussed my feeling that a plausible explanation for the localization of an originally Scandinavian I-Y33765 male lineage in north Somerset can be proposed by linking its patriarch to north Somerset manors that, like Clutton, were owned by men of Scandinavian descent during the two generations that preceded the Norman Conquest.  It seems to me this latest redefinition of genetic relationships on the English arm of I-Y33765 supports this hypothesis.  If you are interested in more discussion on this theme then I suggest you may want to look at these earlier blogs published 24 September 2020, 21 & 23 October 2020 and 11 April, 2021.    



Click on image to enlarge

In the above post, my conclusions about the genetic relationships between the five English Clement men, that I had based on a comparison of their Short Tandem Repeat (STR) 111 marker test results are incorrect.  Consequently, in the above chart the arrangement of branches downstream of Y33767 is wrong and should be ignored.  My mistake has been confirmed by the "next generation sequencing" results from the BigY-700 analysis completed for Clements B742594 in July 2021 (for a full update please see my blog published 8 August 2021). 

It seems to me that it is probably helpful to leave this incorrect post on-line because it illustrates the folly of relying solely on STR markers and nicely demonstrates that only Single Nucleotide Polymorphism (SNP) mutations can be considered a "gold standard" marker for genetic genealogy.

JAC, 8th August, 2021 

Saturday, 8 May 2021

The I-Y33765 clade and Chew Valley, Somerset, England -- Part 2. Y-DNA haplogroup frequencies, surnames and descent clusters

In two previous articles (see October 2020) I have explored the association between the I-Y33765 clade and the Cult of St Clement.  It seems to me that this connection is noteworthy because the Clement hereditary surname which is shared by English men who are derived for the I-Y33765 mutation is generally considered to originate from the name of this early Christian martyr. During the initial phase of conversion of pagan Viking Scandinavia to Christianity the Cult of St Clement became associated with the ruling elites of Norway, Denmark and England.  Clement had been Pope during the first century, and was subsequently martyred by being thrown into the Black Sea tied to a ships anchor.  This method of martyrdom appears to have made him a fitting patron for Viking societies whose existence depended on seafaring, maritime trade and naval prowess. 

In England, as inherited surnames became adopted after the Norman Conquest, some followers of St Clement's cult seem to have adopted his name as their family name and so by the thirteenth century it is found as a patrilineal surname in several English counties.  The dispersed nature of these early recorded instances of the name in England may perhaps suggest its adoption happened separately in different localities and so, as a surname, it became associated with unrelated Y-chromosome lineages. 

The Y-chromosome and patrilineal surnames are inherited in a similar way and hence demonstrate an explicit correlation. In other words, Y-DNA and surnames can be used to demonstrate co-ancestry. In an early review of this correlation (King & Jobling,2009) populations of men with more common surnames showed greater Y-haplogroup diversity implying that common surnames in England were founded many times and hence contained lineages derived from many patriarchs.  So, for the commonest English surname, Smith (652,500 holders), the Y-haplogroup diversity was very similar to that of the general population (see Figure 1a) whereas rare surnames, such as Attenborough (1,065 holders) were associated with a single haplogroup and may have had a single founder.  

In England, these less common surnames that demonstrate clear evidence of co-ancestry have less than 5,600 holders (King & Jobling,2009).  The Clement surname and its close spelling variants (Clements, Clemens, Clemons) is significantly more frequent than this co-ancestry threshold figure (in 2002 Clement variants had 24,200 holders in England, Wales and the Isle of Man) and consequently it has a Y-haplogroup diversity which is very similar to that found in the English male population (see Figure 1b). 

Figure 1: Y-DNA haplogroup frequencies (a) in England (Source, Eupedia, May 2021) (b) in the Clements Surname DNA Project, n = 257 (Source, FTDNA, May 2021).  This comparison shows that holders of the Clement surname represent a Y-DNA haplogroup diversity that is similar to that found in the English male population and this suggests that the name had a large number of founders. Numbers are % figures.  (Note: the majority of members of the Clement Surname DNA Project at FTDNA indicate their paternal origin as being from the USA and hence the data illustrated here should be considered to represent an English speaking North American Clement population.)

From Figure 1(b) we can estimate that one in four men with the Clement surname in England and the USA are likely to have an I haplogroup Y-chromosome and one in five will probably be haplogroup I2a.  As we know, in England, the Clement/s descent cluster originating from the Chew Valley, Somerset, is part of the I-Y33765 clade which itself is a small descendant branch of the I2a haplogroup (see Table 1).

 

Table 1: The I2a haplogroup.  The table shows the descendant haplogroups within I2a leading to I-Y33765. Age estimates are calculated using the method used by Adamov et al.,(2015)

At FTDNA (May 2021) the I2a Haplogroup Project has 3917 members who are each derived for the I-P37 mutation which defines the I2a haplogroup.  Within this sample of I2a men, 303 (approximately 8%) have tested positive for the much more recent Y4252 mutation which is immediately upstream from Y33765 (see Table 1).  Using this information, we can calculate (100 / 8) * 5, and so suggest that fewer than one in sixty men with the Clement surname are likely to have an I-Y4252 haplogroup.  

Now at this stage it seems to me only proper to make it absolutely clear that the method I am using to make this guesstimate is very "rough and ready".  Even so, it does I think allow me to illustrate how the molecular genetics of the Y chromosome can lead us to identify a small population as a descent cluster even in a genetically diverse group like English men with the relatively common Clement/s family name.  As mentioned earlier, in 2002 in England there were 24,200 holders, both men and women, with Clement variant names.  So we can suppose that about 12,100 / 60 men in England may have an I-Y4252 Y chromosome; so perhaps we are considering just 200 or so men.  Given the much larger threshold below which descent clusters have been shown in groups of men sharing an unusual surname (<5,600 holders) it would seem reasonable to assume the I-Y4252 Clement men in England will probably represent descent from a single founder.

From the evidence we have at present all the I-Y4252 Clement/s men with English ancestry are also derived for the downstream Y33765 mutation and have co-ancestry from the Chew Valley, Somerset.  It seems to me this strongly suggests a single founder for the I-Y33765 Clement/s descent cluster and that he probably lived in what is now NE Somerset.  Since we know that the Y33765 mutation formed in Scandinavia during the Iron Age it seems logical to look for reasons why a Scandinavian man might be fathering sons in NE Somerset towards the end of the first milenium.  Not surprisingly this brings us back to the several manors in north Somerset that are mentioned as being owned by "the Dane" in the Domesday Book (Lewis, 2016), and in particular to the manor in the Chew Valley owned by Thorkil "the Dane" at Clutton.

References    

Adamov, D., Guryanov, V., Karzhavin, S., Tagankin, V., Urasin, V. (2015) Defining a new rate constant for Y-chromosome SNPs based on full sequencing data. Russian Journal of Genetic Genealogy 1:3–36

King, T.E.,Jobling, M.A.(2009) What's in a name? Y chromosomes, surnames and the genetic genealogy revolution.  Trends in Genetics 25, 351-360


Lewis, C.P. (2016) Danish Landowners in Wessex in 1066, in Danes in Wessex, Eds Ryan Lavelle & Simon Roffey, Oxbow Books, p 172-211



 

 

 

Sunday, 11 April 2021

The I-Y33765 clade and Chew Valley, Somerset, England -- Part 1. Documentary sources before the introduction of church registers, circa 1538

At present the earliest known distribution for the I-Y33765 clade, in both Sweden and England, is very localised; in Sweden within Tjust, Småland and in England within the Chew Valley, Somerset.  Until recently it has appeared that in England the clade also had an ancestral lineage from south Gloucestershire but it now seems more probable that this too represents a genealogy that can be traced originally from the Chew Valley area.  

Previously I have suggested that the genetic and historical evidence make it possible that migration of the clade from Scandinavia to England occurred in the late Viking period most probably with the participation of a man or several men from Tjust in the campaigns of Sweyn Forkbeard or his son, Cnut the Great.  Following Cnut becoming the English king in 1017 it seems to me that an I-Y33765 male very likely became a resident in one of several manors in North Somerset that, in Domesday are recorded as being held by men described as "the Dane" (Lewis, 2016), and that it is his descendants who are now testing positive for the Y-DNA SNP, I-Y33765 and for the more recent English mutations.  Up until now all five of these men, representing three lineages that are distinct over the last two to three hundred years, have variants of the Clement hereditary surname.

In this article I intend to begin an investigation of the documentary evidence for the connection between the "Dane" who first set up his home in north Somerset circa 1020-1060 and the three I-Y33765 "Clement/s" genealogies that originate out of Chew Valley in the seventeenth and eighteenth centuries.  To do this I will describe what I consider to be a plausible historical narrative based on documented sources to follow the hereditary surname "Clement/s" in the manors and parishes of Chew Valley over 600-700y. In this first installment I will consider the years 1060 to 1538.

At the outset of this period Domesday gives us evidence for just a single Scandinavian manor, Clutton, that we may reasonably propose to be within the catchment of the River Chew.  Domesday records that in 1060 this manor was held by Thorkil "the Dane" (Lewis, 2016).  At that time it seems to have been an "outlier" from a significant grouping of five Scandinavian manors further west adjacent to the Severn estuary.  Thorkil held two additional manors in that group, Chelvey and Backwell.  Domesday also records that in 1086 the ownership of Clutton had passed to Geoffrey, Bishop of Coutances, who was a powerful Norman landowner and friend of William the Conqueror and that Gregory's tenant at Clutton was William de Monceaux.  In addition Geoffrey held the manor of Cameley which joins Clutton on its southern boundary and the manor of Farmborough which is contiguous to the northeast. While Geoffrey kept the lordship of Cameley his tenant at Farmborough was again William de Monceaux.  

 

Figure 1: Distribution of individuals named Clement in the 1327 Lay Subsidy Roll of Somerset (red circles). The 1327 Lay Subsidy Roll for Somerset contains the names of about 10,000 inhabitants of that county whose movable assets were assessed at a value of ten shillings or more.  Only five persons with Clement variant surnames are included.  Three of these live in the Hundred of Chewton Mendip, each within 1km of the Manor of Clutton which, in 1060, was held by Thorkil "the Dane".  According to the entry in Domesday recorded in 1086 the Manor of Clutton contained 23 households including 10 villagers, 12 smallholders and a slave.  Because of it's Scandinavian ownership, for perhaps two generations before the Norman Conquest, it is plausible to speculate that I-Y33765 males lived in one or more of the Clutton households in 1060.  The map of Somerset used to illustrate this article was produced by Emmanuel Bowen in 1750.

It seems to me Greoffrey's Lordship over Clutton, Cameley and Farmborough may be significant for our investigation.  These three manors skirted a large portion of the southern slopes above Chew Valley and it is in Cameley and Farmborough that we have our earliest documented use of the Clement surname in the area.  

Figure 2: Documented locations for Clement individuals in the vale of the River Chew before the introduction of church registers circa 1538 (dates in red) and earliest documented locations for Clement genealogies that are derived for I-Y33765 (dates in purple). 

First in Cameley in 1283, William Clement is recorded as witness on a deed for land tenure (Somerset Heritage Centre, DD/HI/A/47/8) and some forty years later Adam Clement is recorded as liable for 12 pence tax at "Hentone [Blewitt] et Cameleghe" in the Lay Subsidy Roll of 1327 (Dickenson, 1889).  In the same year, in the Camley tything of [Temple] Cloud (entered as Londe in the 1327 Lay Subsidy Roll), Johanne Clement was assessed at 12 pence and Willelmo Clement at six pence.  So the 1327 Lay Subsidy Roll for Somerset records three men with the Clement name living within a kilometer of Thorkil the Dane's manor of Clutton.  The 1327 Roll lists about 10,000 inhabitants of Somerset whose "movable goods" were valued at more than ten shillings and was drawn up in the first year of the reign of Edward III.  In this Somerset population survey only five individuals are named Clement; they are the three we have noted in the Hundred of Chiwton (Chewton Mendip) and one each in the hundreds of Coker and Wyntestok (Winterstoke) (see Figures1 & 3). 


Figure 3: Annotated (red text) extract of FH Dickinson's published transcription of the 1327 Lay Subsidy Roll for the Tythings of Temple Cloud and Hinton Blewett & Cameley.  It shows the three Clement individuals within the Chewton Mendip Hundred.  This taxation was levied at the rate of one twentieth the assessed value of an individuals "movable goods".  These items included large farm animals and cash crops but excluded clothing, household goods, food in the larder and farming equipment.

It seems to me this evidence from the 1327 Lay Subsidy Roll substantiates a particular concentration of the Clement surname in the Chew Valley area adjacent to the Manor of Clutton in the early fourteenth century. In other words, about ten generations after Domesday records that manor was held by a Scandinavian lord, "Thorkil the Dane", a group of households of the "middling sort" in the neigbouring parish of Cameley represent the highest density (60%) of the Clement surname.in the whole of Somerset.  Other deeds mention the same Clement family at Cameley in the period up until 1387.  Given the association between the Clement surname and the I-Y33765 SNP and the migration of that mutation from Scandinavia circa 1000, it seems to me we might interpret this documentation as supporting the possibility that men with this haplogroup whose patriarch had originally lived in the manor of Clutton had moved into Cameley during the two centuries 1086 to 1283 and had subsequently lived there at least until the later fourteenth century (Figure 2).  It is possible that sometime later some of these Clement lineages moved into the upper Chew Valley around Stowey and the Harptree villages. In 1283 Cameley was held by the de Marisco family who had gained it by marriage circa 1200.

By 1154 ownership of Geoffrey's manor at Farmborough had passed to William de Ferenberge who at that date gave some land to the Abbey of Keynsham. The manor of Farmborough is in the Keynsham Hundred.  In the lay Subsidy Roll of 1334 at "Farnbergh" John Clement was assessed for 2 shillings tax. This suggests to me that by the mid fourteenth century the I-Y33765 mutation had also moved from Clutton into Farmborough. This is the first record we have of expansion towards the lower Chew Valley around Compton Dando (Figure 2). By the late 14th century Farmborough had passed to the Stafford family, who held it until 1470.

The earliest documentary evidence we have at present for the Clement name in the lower valley of the River Chew is circa 1518 when Thomas Clement, husbandman of Compton Dando, is the plaintiff in a dispute over two manors in that parish, Grubbeswick and Sewardswick for which he and his wife, Johan, held the lease (National Archive C1/487/1 & C1/487/2). The defendants are John Rede, husbandman, and Isabel Clement, widow, both of Burnett. This proceeding in the court of Chancery and the almost contemporary Lay Subsidy Rolls of 1522-24 and 1524-25 in the lower Chew Valley parishes together record some ten Clement individuals in that area.  It seems to me this number of Clements with sufficient goods to be subject to taxation suggests the family, and hence I-Y33765 men, were living there for decades before the 1520's (see Figure 4). 

Figure 4: Documented locations for Clement individuals in the parishes of the lower Chew valley (Keynsham Hundred) before the introduction of church registers circa 1538 (dates and locations underlined in red).  The supposed original locus for I-Y33765 in the Manor of Clutton circa 1060 is circled (near bottom centre) as are it's hypothetical centres during the late 13th and early14th centuries in Cameley and Temple Cloud.  

In 1538, Henry VIII ordered that every parish should provide a register in which the priest would record each baptism, marriage and burial within his congregation. In the Chew Valley surviving parish registers record events from the mid 1500's and using these we can construct more coherent genealogies. Clements YS32045, who is I-Y33767+, has such a family history that originates with the marriage of his seven times great-grandparents, Francis Clement and Katherine Peacocke, at St Mary, Compton Dando on 29 July 1663. It seems to me that at present the most plausible hypothesis we have to explain the several similar I-Y33765+ genealogies whose origins are clustered in the Chew Valley is that their common patriarch lived in the vicinity of the Manor of Clutton at the time of Domesday.

Click on images to enlarge

References

Dickinson, F.H.(1889) Kirby’s quest for Somerset. Nomina Villarum for Somerset of 16th of Edward the 3rd. Exchequer Lay Subsidies 169/5, which is a tax roll for Somerset of the first year of Edward the 3rd. County rate of 1742. Hundreds and parishes etc. of Somerset as given in the census of 1841. Somerset Record Society, Vol 3. 360pp
 

Lewis, C.P. (2016) Danish Landowners in Wessex in 1066, in Danes in Wessex, Eds Ryan Lavelle & Simon Roffey, Oxbow Books, p 172-211

 

 


Saturday, 13 March 2021

The I-Y33765 clade-specific SNP mutation rate and age estimations

Estimating the time to most recent common ancestor (TMRCA) of two men by using SNPs found in the non-recombining regions of the Y-chromosome is helpful in better understanding their supposed relationship.  

To attempt this estimation it is necessary to know the number of reliable SNPs that have formed in each of their Y-chromosomes in the period by which they are separated.  If their Y-chromosomes show that they share a SNP such as I-Y33765, and we want to estimate the time to their most recent shared male ancestor who also carried the I-Y33765 mutation we start by counting the number of reliable mutations that have formed on their Y-chromosomes since (or downstream from) I-Y33765.  

From the chart below, and using the example of Jacobsson IN70815, we count the observed number of high quality SNPs (those shown in red, indicating they are positioned within the CombBED region of the Y-chromosome as defined by Adamov et al., (2015)) that are listed on the branches of the chart that link Jacobsson to I-Y33765.  In this way the pink annotations link six such SNPs that are of a suitable quality to be used in our calculation.  

Next, because each Big Y-700 test will analyse or provide "coverage" of a slightly different length or proportion of the 857 segments that make up the complete CombBED region, we apply a correction to adjust the number of observed SNPs to what they would have been if all CombBED segments (CombBED "coverage" length used by YFull is 8,467,165bp) had been fully analysed.  The formula for this SNP correction is:

 (Observed number of SNPs / Coverage in Big Y-700 test) * Coverage length of CombBED)

In the case of Jacobsson IN70815, his Big Y-700 test gave "coverage" of 8,223,356bp.  So, entering his detail into the SNP correction formula we get:

 (6 / 8,223,356) * 8,467,165 = 6.18 SNPs

Hence, we have 6.18 mutations that have occurred on Jacobsson's ancestral line since the formation of I-Y33765.  As explained in an earlier post, a 19 generation Swedish pedigree suggests that within the I-Y33765 clade a new mutation occurs every 109.5y.  Consequently we can estimate Jacobsson's TMRCA for the Y33765 mutation by multiplying the corrected number of SNPs by the clade-specific mutation rate and then adding an allowance for Jacobsson's age (YFull add 60y) as follows:

(6.18 * 109.5) + 60y = 737 ybp  

 
 Click on chart to enlarge image
 
By applying this method to all six NGS results that we have at present within the I-Y33765 clade we can produce estimates of TMRCA for the five phylogenetically significant SNPs within our clade (Table 1).
 

Table 1: Single nucleotide polymorphism (SNP) age estimates made using the mutation rate
 observed in the Nils Swennsson pedigree

 References

Adamov, D., Guryanov, V., Karzhavin, S., Tagankin, V., Urasin, V. (2015) Defining a new rate constant for Y-chromosome SNPs based on full sequencing data. Russian Journal of Genetic Genealogy 1:3–36

Thursday, 18 February 2021

I-Y33765 draft tree February 17th 2021

This latest version of our I-Y33765 phylogenetic tree includes the recently completed 111STR upgrade analysis for Dahlberg IN81271.  

From his previous 37STR result it had seemed likely that Dahlberg and Hallberg YF80422 may have shared a common direct-line male ancestor within the last 200-300y. However, based on his new upgrade result it is now clear that this was an incorrect assumption.  It now seems more probable, based on STR comparisons between all four Swedish men for whom we have confirmed Y33765 derived (+) status, that his lineage, and those of Hallberg YF80422 and Jacobsson IN70815, diverge at the level of BY198548.  This relationship is shown on our revised chart but, as yet, Dahlberg's status for the BY198548 SNP has not been confirmed by PCR.

Click on chart to enlarge

 

Tuesday, 2 February 2021

I-Y33765 draft tree January 14th 2021

The style of our latest I-Y33765 phylogenetic tree has changed from that used in previous drafts.  The intention is that this new format should make it easy to see some useful characteristics of the genetic markers directly from the chart.  

For example the names of single nucleotide polymorphism (SNP) markers are now shown in either red or green; those in red are located within the CombBed (non-recombining) regions of the Y-chromosome and consequently we can have high confidence that these SNPs are true mutations suitable for use in age estimations.  On the other hand SNP names shown in green or purple are in less stable areas of the Y-chromosome and may consequently be less reliable and possibly false positives.  Using the high confidence SNPs to calculate the time to most recent common ancestor (TMRCA) for a particular mutation, we can total the number of red SNPs shown on each downstream branch and multiply that number by the clade-specific mutation rate as estimated using the Swensson pedigree (see post January 2021). 

In a similar way the genetic distance (GD) between individuals who have each taken an 111marker short tandem repeat (STR) test can be found directly from the chart.  On the branches of the chart ellipse symbols contain the GD applicable to each particular branch and so it is possible to quickly work out the distance between men who have tested 111STR by adding these GD numbers along the branches that join them. The small version of the chart is annotated with three examples to illustrate this approach.  Hallberg YF80422 is GD17 from Clement IN82043 at 111STR (GD symbols linked by purple line), while he is GD7 from Eklund IN78036 (GD symbols linked by orange line).  The final example (GD symbols linked by pink line) illustrates the GD5 relationship between Clement 236748 and Clement IN82043.

The orange dash symbols on a portion of the Swedish arm of the chart, linking Jacobsson IN70815 and Hallberg YF80422, shows the position of the 19 generation Swensson pedigree used to calculate our clade-specific SNP mutation rate. 

Click on charts to enlarge




Warlords, foederati, princes or pirates: Exploring some characteristics of the men involved in the star cluster expansion downstream of I-Y4252

There would seem to be something remarkable about the man who was the founder of the I-Y4252 haplogroup.  We can see this clearly from the e...