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The Sambells DNA Project

Article by Dene Sambells

#Introduction

I read molecular biologist Bryan Sykes book “The Seven Daughters of Eve” about his new DNA testing methodology soon after its release in 2001. I was blown away by its content. Having graduated with a BSc in Biological and Earth Sciences in 1986, and having taken some papers in Genetics I was able to comprehend the potential he had unlocked for genealogists. By this time I’d spent a chunk of time working back through the SAMBELLS BDM records (1837 – 1990) in England, the census returns (1841 – 1881) of England’s West Country, and then the Parish Records of Stoke Damerel, Devonport, Devon (1650 – 1837), and its neighbouring parishes.

At the time I was aware that Sykes academic home at Oxford University had developed DNA testing for paying customers via Oxford Ancestors but its strength initially lay in linking to the maternal history of the seven major women said to have migrated from Africa some 20000 years previously. Testing of man’s male history is a more recent development and both its cost and genealogical worth have become more affordable and valid.

Thankfully, a number of SAMBELLS (and variants) genealogists have researched their male lineage (patrilineage) back over many generations. This research has been based upon a series of written records stretching back some 500 years or more – generated within western cultures growing religious, political and civil organisation of society. The link in all these is the passing of a common surname between father and son. This surname may have altered over time when parish cleric’s changed or an individual married in a neighbouring parish or county (e.g. SAMBLES to SAMBELLS). Assumptions have been made based on any discontinuity, but genealogical certainty lacks. This is where DNA testing can either support or disprove patrilineage by drawing together the seemingly related but disparate strands of each family ‘clan’.

Participants in this project will therefore be looking to confirm the exclusive male line decent from a single male ancestor – the patriarch – identifiable within written genealogical time by a shared surname. This definition can be extended to include all cousins of these male descendants whether male or female. The initial stages will focus upon confirming the degree of relatedness (haplotype) of the participants to what we assume will be our Most Common Recent Ancestor (MCRA).

Potentially the testing could also disconfirm membership of the group. Reasons could include:

  1. Invalid inferences made with regards previous research data
  2. Inaccuracy in historic data
  3. Non-paternity events. Adoption, out-of-wedlock birth, elective name change. [Population Geneticists estimate these situations could occur 2-5% per generation].

Ultimately the strength of our project will rest upon the number of participants, and the quality (Genealogical Proof Standard) of our research. Whilst a small number of comparisons will confirm shared lineage and an MCRA dated to within a century or two, the greater the number of participants whom are supported by well-documented sub-lineages will provide for greater correlation and strength in its reported outcome. Therefore the desire of the SAMBELLS DNA Project is for as many potential male SAMBELLS (and variants) internationally to partake in the chosen testing.

Having shelved a large amount of my research over the last decade whilst busy with a young family and career, it’s thanks to Frank SAMBELLS exciting and timely website development that he’s reignited my desire to explore our common genetic ancestry.

#DNA Backgrounder

Let’s first learn a little about our DNA (apologies for the technical terms) and what it can tell us. I’ve spent some time reviewing the literature and the online resources of testing agencies, and comparing their services with a view to recommending how we conduct our project.

Scientific advancement over the last few decades has led to the unraveling of man’s genome. The discovery of DNA and the genetic code it holds within its helical strands has led to the decoding of some 25000 genes which are responsible for the manufacture of proteins – the essential building blocks of human bodies.

There are some 3,000,000,000 nucleotides within the entire human genome. Nucleotides form the basic structural unit of nucleic acids such as DNA. They consist of a sequence of (A)denine, (T)hymine, (G)uanine and (C)ytosine chemicals. The entire code can be found within the nucleus of every cell of our bodies. These genes are structurally packaged in 23 pairs of chromosomes and surprisingly 95% of the ATGC coding therein is described as ‘junk DNA’ – not coding for any gene – and its purpose still to be discovered.

Twenty two of the chromosomal pairs are deemed autosomal with one half of the pairing donated from each parent during reproduction in a process called meiosis. The twenty third pair is responsible for the gender of any offspring and consists of a combination of the X and Y chromosome. The mother always donating an X as females are XX, whereas the father either an X or Y, with males XY.

Also to be found within cells and outside the nucleus, is another separate piece of circular DNA called Mitochondrial DNA which is very important in tracing maternal ancestry (matrilineage).

The DNA sequence – whether nuclear or mitochondrial – can be decoded and written out for scientists to interpret. The code ……. TTCGATGCATCGACTTT ….. is on the whole the same for all humans, but occasionally during the reproductive process of meiosis errors can occur. These errors have varying affects, but on the whole (especially in the structural component) don’t result in any harm to the host. The importance to genealogists of the errors – known as mutations – is that they have developed over millions of years and are passed on to subsequent generations. This akin to the written variance in parish documents which has resulted in the multiple spelling of SAMBLE, SAMBEL variants still in existence today. The specific changes at any location are called Single Nucleotide Polymorphisms (SNP’s).

#Testing Options Considered

The most popular ancestry tests are Y chromosome (Y-DNA) testing and mitochondrial DNA (mtDNA) testing, which test direct-line paternal and maternal ancestry, respectively. Before we explore the Y-DNA tests of most importance to the Sambells DNA Project, it’s important to understand that a range of other test options are available with differing objectives.

##A) Autosomal DNA

Whilst we will be endeavouring to work back through our Patrilineage as a group, it is now possible to research the autosomal chromosomes to identify all of ones close cousins and relatives. By scanning between 500,000 and 1,000,000 SNP’s and comparing long stretches of these on the same chromosome can indicate close cousin or relative relationships. The shared inheritance of autosomal DNA see’s the cross-over phenomenon of replication during meiosis decreasing the matches by a factor of 3-1 each generation. The genealogical value at present is limited due to testing agency database sizes and would provide greatest benefit to ‘daughtered out’ patrilineages.

##B) BioGeographical Ancestry (BGA) – ethnographic

This process compares the results of testing 71 autosomal SNP’s called Ancestry Informative Markers (AIMs) of a participant with a known database. It reports on the population group genetic mixture of the individual, expressed as percentages of Indo-European, East Asian, Native American and Sub-Saharan African. It cannot differentiate between recent or ancient inheritance and needs to be used in conjunction with other evidence.

##C) Mitochondrial

Within all human cells lie mitochondria. These small organelles are inherited from ones mother, having been derived from the egg during fertilisation. Theories suggest this short circular piece of mtDNA may be a hangover from a symbiotic bacterium that has been carried through human evolution. It has benefited mankind by providing energy to the cell. As this separate section of DNA does not recombine during reproduction it remains unchanged during the passing from mother to child, and therefore can be traced back through time from daughter to mother to grandmother … mtDNA is constructed of 16569 bases of DNA, coding for 37 genes. Each human cell contains between 100-10000 copies. SNP mutations of mtDNA occur rarely and two key areas have been identified. These have been designated as hyper-variable regions (HVR-1) nucleotides 16001 – 16569, and (HVR-2) nucleotides 73 – 577. These can be sequenced along with the coding region (balance of the sequence) and comparisons made with a single randomly chosen mtDNA sequence called the Cambridge Reference Sequence (CRS).

These reported variances allow mtDNA comparisons to be made with databases of other people, and can also be used to determine the time period since any two individuals shared a most common recent ancestor (MCRA), and the person’s matrilineal haplogroup, and haplotype.

It’s these haplogroup results which allow anthropologists to study long-term human migration, and formed the basis of Bryan Sykes’s Eve, and her 7 daughters. The dispersion of man from Africa has subsequently been mapped based on these maternal DNA results into 30 groups and further defined into many subgroups.

Whilst of interest to genealogists the precise resolution of time to the MCRA is not as precise as that for the Y-DNA tests, and with most cultures passing the male surname through the generations any female maiden name gets unfortunately lost. Whilst limiting its usefulness for our project a number of participants may be interested in testing this to determine matrilineal relationship to others.

##D) The Sex Chromosomes: X Chromosome

With both males and females having at least one X chromosome in their gender chromosome pair, it could be construed that it could be valuable in tracing either our maternal and/or paternal histories. The problem with the X chromosome genealogically lies in the fact that during the recombination process of meiosis in females( XX), a random mixing of information and genes occurs. There are roughly 100 genes encoded in the 153 million nucleotide base pairs of the X chromosome and this mixing leads to difficulties in looking for a ‘signature’ that is passed on generationally. Testing has been started working on X-DNA regions that are inherited intact over several generations but its benefits are directed to researchers with ‘little previous knowledge’ of either maternal or paternal lineage.

The consistency of the mtDNA of mitochondria has been the reason genealogical matrilineal testing has been focussed therein.

##E) The Sex Chromosomes: Y chromosome

  • [After his research and review of the topic and comparison of the various types of DNA testing, Dene recommends that the first phase of our project would benefit most by having Sambells males pursue testing of the Y-DNA]

So what about the Y chromosome during meiosis?. Fortunately for genealogists the much smaller Y chromosome – a mere 58 million base pairs coding for 83 genes – has only 5% recombination at its tips (telomeres) where 9 genes interchange. This leaves the remaining 74 genes passing from father to son through the generations relatively unchanged, apart from those naturally occurring mutations. These subtle variances provide us with the means to analyse the relationships between individuals and populations.

STR – Haplotype: Y chromosome analysis concentrates on sequencing the nucleotide bases in short segments of DNA called short tandem repeats (STRs). These areas have been identified as statistically important markers, and designated as DYS numbered regions (DNA Y-chromosome Segment numbers) e.g. DYS392, with values of 11, 12, 13, 14, 15 and 16 – with 13 being most common. STR testing provides a personal haplotype, and can be used to suggest which haplogroup an individual belongs.

SNP – Haplogroup: In addition to STR’s it is possible to assess mutations that occur at other single nucleotide positions in the Y chromosome sequence called single nucleotide polymorphisms (SNP’s). These identify changes that occurred at distinctive times in man’s combined history and separates human history into about 20 distinct major groups called haplogroups.

#Genetic Distance is revealed by Y-DNA testing

Testing the Y-DNA of two males sharing the same surname, and finding the results closely match provides strong confirmation they descend from a common ancestor. In addition though the stability of the Y-DNA and any change being statistically predictable, provides for measurement of the differential number of mutations that have occurred over time between two tested males to act as a generational clock – the genetic distance back to the Most Common Recent Ancestor (MCRA).

The sensitivity of the average mutation rate can range between 1 per billions to 1 per several hundred generations. The areas where the fastest mutation rates occur are the aforementioned STR’s.

Most tests focus on between 12 and 67 STR markers and whilst a greater number of markers can be included it doesn’t necessarily provide for a greater level of accuracy. Recent research has shown the average rate of mutation across each STR can vary by as much as 10 times so both the number and average rate of mutation of any marker is important in selecting a testing regime.

#Sambellls DNA Project Recommendation

A number of international testing agencies have been operating over the previous two decades. They have all developed a range of mtDNA, Y-DNA, X-DNA and Autosomal testing offers and have built databases and provided a platform for the maintenance of surname projects.

With Y-DNA testing the focus of our surname project, my initial leaning toward the Oxford Ancestors offer had to be assessed against others. Bryan Sykes business was founded at England’s Oxford University and based on mtDNA research. Whilst offering y-DNA testing, and Sykes having penned further books on the Y-chromosome and Britain’s tribal history I found other agencies are providing more cost-effective, more comprehensive STR & SNP marker test ranges, and larger databases for comparison.

Family Tree DNA (FTDNA) ticks all the boxes. They offer a cost competitive range of Y-DNA marker tests, with the world’s largest database. They have a website that supports privately administered surname projects and discussion forums, which has lead me to recommend them to those looking to participate in our project going forward.

A comparison of DNA test prices can be viewed at the following link:

A description of the registered “Sambells Group Project” at Family Tree DNA can be viewed at the following link:

#Test Markers for the Most Recent Common Ancestor

Family Tree DNA offer the following tests which are most relevant to our search for our Most Recent Common Ancestor: Y-DNA37, Y-DNA67 and Y-DNA 111.

The recommended test regime for participants is Y-DNA37. The increase to 67 markers improves the 95% confidence level of test results from within the last 8 generations to 6 generations, and 111 markers from 6 to 4 generations.

A benefit for users is that FTDNA store the DNA sample for 25 years and for a fee (approximately the difference in the initial tests) they will upgrade if requested from 37 to 67, or 111. I’ve initiated a SAMBELLS Surname Project which sees the test price discounted as listed:

Y-DNA37 US $149.00 + postage

Y-DNA67 US $238.00 (subsequent upgrade from 37 will cost a further $99)

Y-DNA111 (subsequent upgrade from 67 will cost a further $129)

[I have personally opted for the Y-DNA 67 test but have added the Full mtDNA test offered as the SuperDNA test which cost $US 554 – this because I have an extensive matrilineage and have always wanted to understand which of the maternal clans I descend from]

Family Tree DNA host the largest DNA database in the world which is publicly searchable (www.ysearch.org) and allow the attachment of family tree pedigrees. They also have the ability to incorporate other results if participants have tested with other providers, and have online public forums for participants and project administrators.

#Genographic Project

A partnership was formed in 2005 by National Geographic and IBM with support by the Waitt Family Foundation and public participation through Family Tree DNA to map how humankind populated the Earth.

The core of the project is to sample DNA from indigenous populations to map ancient migratory patterns. The FTDNA test I’ve recommended, allows participants to optionally upgrade their personal test results to the Genographic Project [these are stored anonymously to protect individual privacy] at the nominal cost of $US 15.

How is the test conducted, and how do FTDNA provide Privacy of your results ?

Important : ONLY VALID FOR MALE SAMBELLS (and variants).

The test kit consists of two swabs that look like tooth brushes. These are used to simply and painlessly swab the inner lining of your cheeks for about thirty seconds to gather sufficient cells to conduct the test. The swab heads are inserted into tubes of preservative liquid and then posted off to the lab. No needles or blood samples are used.

A form will need to be filled out to release your information to the surname project database, and only the project coordinator will have access to the information other than yourself.

Privacy is assured because the testing facility will not have access to your name. Only your unique Kit ID number will accompany your collection tubes to the lab. Results will be entered into a secure non-web-based database, and the lab will advise us (sample provider and project co-ordinator) of any matches between two ID coded numbers. The information placed in FTDNA’s Surname Database library will only display your last name on their website. However if you authorise it and sign the release form, you can have your contact name and e-mail address displayed. No other specific information about you will be available at the website.

#Sambells DNA Project Administration and Project Participation

Dene Sambells has volunteered to act as Project Administrator and is happy to answer any questions prospective participants may have. The FTDNA website has an excellent Questions and Answers section. Their website link is listed below under References. As we increase our level of participation over the coming years we can more closely define our longer term objective(s).

Frank SAMBELLS (Curator of SAMBELLS Family Geneaology) has some excellent pre-1500’s research which may shed light upon our Most Common Recent Ancestor. As we define the potential origin of the SAMBELLS surname we will become more inclusive of the range of surname variants such as SENPOL, de St Pol, and Candavene in Europe.

Both Dene and Frank welcome your interest and look forward to your participation in our DNA Surname Project.

[On April 20, 2012 Dene 2 posted off his DNA sample and will advise when the results have been received and the FTDNA Surname Database link has been activated.]

#References

 

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