Download Past History of the Retson Family based on DNA evidence Written

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Minimal genome wikipedia , lookup

Oncogenomics wikipedia , lookup

Genome evolution wikipedia , lookup

DNA damage theory of aging wikipedia , lookup

Mutation wikipedia , lookup

Genomic imprinting wikipedia , lookup

Cancer epigenetics wikipedia , lookup

X-inactivation wikipedia , lookup

Human genome wikipedia , lookup

Epigenomics wikipedia , lookup

Polyploid wikipedia , lookup

Genomic library wikipedia , lookup

Polycomb Group Proteins and Cancer wikipedia , lookup

Molecular cloning wikipedia , lookup

No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup

Nucleic acid double helix wikipedia , lookup

DNA vaccination wikipedia , lookup

Epigenetics of human development wikipedia , lookup

Genomics wikipedia , lookup

Nucleic acid analogue wikipedia , lookup

Chromosome wikipedia , lookup

Site-specific recombinase technology wikipedia , lookup

Genome (book) wikipedia , lookup

DNA supercoil wikipedia , lookup

Genetic studies on Bulgarians wikipedia , lookup

Gene wikipedia , lookup

Deoxyribozyme wikipedia , lookup

Nutriepigenomics wikipedia , lookup

Mitochondrial DNA wikipedia , lookup

Cre-Lox recombination wikipedia , lookup

Cell-free fetal DNA wikipedia , lookup

Non-coding DNA wikipedia , lookup

Designer baby wikipedia , lookup

Therapeutic gene modulation wikipedia , lookup

Vectors in gene therapy wikipedia , lookup

Helitron (biology) wikipedia , lookup

Extrachromosomal DNA wikipedia , lookup

History of genetic engineering wikipedia , lookup

Point mutation wikipedia , lookup

Microevolution wikipedia , lookup

Artificial gene synthesis wikipedia , lookup

Genetics and archaeogenetics of South Asia wikipedia , lookup

List of haplogroups of historic people wikipedia , lookup

Haplogroup T-M184 wikipedia , lookup

Genealogical DNA test wikipedia , lookup

Haplogroup T-L206 (Y-DNA) wikipedia , lookup

Haplogroup I-M438 wikipedia , lookup

Past History of the Retson Family based on DNA evidence
Written by Marc Yorke
General comments:
In the spring of 2015 Jim Retson had his DNA profile tested by 23andMe1 .
The results come in several forms, including his Y-Chromosomal (Y-DNA) type which indicates
the paternal ancestry, mitochondrial DNA (mtDNA) which indicates his maternal ancestry, and general
genotype of somatic chromosomes which gives an indication of the relative contributions from different
ancestral populations.
With respect to both Y-DNA and mtDNA, the results are given in the form of a specific
haplogroup which is generally reported in the fashion of Letter-number-letter (e.g. R1b1b2). Each
haplogroup can be said to have sub-groups (known as subclades) which allow smaller and smaller
groups to be tracked. There additional ways in how haplogroups can be reported so you will
occasionally see references such R-u106. In these cases they are referring to the specific mutation that
gives rise to a particular subclade (in this case, R1b1b2a1a1 which is my own haplogroup). Further
confusing the issue is that some letter designations are used for both Y-DNA and mtDNA (for example R)
so it is important to consider which is being spoken of while researching.
How DNA allows us to track back:
On the level of the individual our DNA acts like a clock, ticking with random mutations that occur
at a relatively constant rate and we can time the changes over time. Some of these changes are in
unimportant parts of our genes and therefore completely random as to whether they become “fixed” or
not while others have affects that give rise to characteristics that are influenced by evolutionary factors.
In populations, the overall rate of change is determined largely by population size, so that more changes
will be seen over a short period in a large population as compared to a small population (which would
show fewer changes in the population). This information allows us to determine the overall size of a
population over a long period.
As these mutations accumulate over time there arises groups of mutations which can be
identified as coming from a single source and form a haplogroup (a haplogroup is distinct from our
overall collection of genes we might contain which forms our genotype). Movements of people within a
Haplogroup can be traced over time by looking at where concentrations of the Haplogroup are found in
modern populations and by verifying this with fossil DNA records.
Results indicated he was 67.6% Anglo-Saxon (R1b1b2), 11.6% Franco-German, 3.3% Scandinavian,
15.1% Broad North-Western Europe, and 1.6% Iberian. His DNA also contained 2.9% Neanderthal DNA
which puts him in the 85-90% percentile of Europeans tested.
Paternal (Y-DNA) line:
The Retson male family line (Y-DNA) is an ancient one and is defined as I1 (eye one). It is
thought that it represents part of the first wave of modern humans out of the Middle East which
migrated out through present-day Greece and the Balkans2. The initial group was formed by
Haplogroup IJ3. These early migrants reached the Balkans about 38,000 years ago and it was at this
point that Haplogroup I is thought to have arose through a division of the IJ haplogroup into the I and J
subgroups. Interestingly, this makes the I (and technically J) Haplogroup the only modern Haplogroup
which actually arose in Europe. All subsequent haplogroups which entered into Europe arose in the
Middle East.
It is important to recognize that these early ancestors of the Retson family line in Europe were
not the Indo-European group that came to make up most of European genetic background (including the
various Germanic tribes which include the Anglo-Saxons). Instead, they represented the early huntergatherer Cro-Magnon Man that went into Europe. It was the interaction between these early modern
humans with the existing populations of Neanderthal peoples that has been of such interest recently.
As a result, these early Europeans accumulated more of the Neanderthal genetic input than did later
migrants and this is seen in a higher-than-average proportion of Neanderthal DNA within the Retson
genome as seen by the tests done by Jim Retson.
Haplogroup I separated at an early point (about 26,000 years ago) into the I1 and the I2 groups.
Initially both of these new haplogroups found throughout Europe, along with the parent IJ group and
the new J group. However, something interesting happened to the I1 haplotype whereby it showed a
remarkable stability over a long period. The general conclusion of this is that at some early point this
haplogroup was represented by a very small population who became isolated for a long period of time.
It is generally considered that the last period of Glacial Maximum (about 22,000 years ago) resulted in a
small group finding refuge in isolation for an extended period of thousands of years.
During the period of 18,000-12,000 years ago while the last Ice Age waned and the ice receded
there were new waves of immigrants into Europe. These new migrants were made up of the IndoEuropeans in the form of Haplogroups R1a and R1b. Originating in present-day Anatolia, It is thought
that these new groups had developed rudimentary agriculture in the form of animal husbandry. This
allowed them to stabilize their food source and populations grew more rapidly as a result. It also led to
the need for more lands and a rapid migration into areas recently cleared of ice. Their ability to support
a larger and more stable population led to them rapidly occupying areas previously occupied by the
people of the IJ, I1 and I2 haplogroups and so these original groups came to form less and less of the
population in Europe while the Indo-Europeans became the dominant group. The exception to this rule
was in the “hard to reach” places of Europe, such as the area of present day Scandinavia.
Early on, Scandinavia showed a population which included both the I1 and I2 haplogroups.
However, by the time the ice had receded and the new Indo-Europeans were arriving the I2 group had
largely disappeared from the area, although the I2 group remained elsewhere where it further divided
into new sub-groups. The suggestion has been made that a small group of I1 peoples were able to
survive through the brutal conditions of the Ice Age by the use of animal husbandry which may have
come from early contact with the Corded Ware Culture of the R1a-haplogroup. The net result was that
for many thousands of years a very small group of I1 people held on while the local I2 groups perished
and so I1 became the dominant group within the area of Scandinavia.
The R1a haplogroup was, as I’ve said, the first indo-European group to have contact with the
Cro-Magnons of Scandinavia as represented by the I1 haplogroup and these R1a peoples probably
brought herding to the previously strictly hunter-gatherer original settlers. These new-comers would
later come to form the Eastern European and Slavic peoples and explains the presence of a high
percentage of Broadly North-Western European genes within the Retson Genotype. Later, Scandinavia
saw immigration from the related R1B haplogroup. These peoples were the founders of the Germanic
peoples which included the Anglo-Saxons. Through this last immigrant population, the people in
southern Scandinavia acquired the proto-German language and northern European culture. Further
north the Fins and the Saami belonging to haplogroup I1 was less influenced genetically by the R1b
influx and generally did not acquire Germanic language and culture to the same extent.
As the ice sheets melted members of haplogroup I1 could be closely identified with the people
of what was to become Norse Scandinavia, although both R1a and R1b populations were becoming
common. Further south, the Anglo-Saxons and other Germanic tribes were living on a land-bridge that
connected England and Ireland to Europe. By about 6000BCE this land-bridge had sunk beneath the
North Sea and now forms the Doggers Banks and England became separated. During this period the
total population of all modern humans in Europe was as low as 3,000 individuals and no more than
30,000 individuals.
The Retson paternal line can be established in high likelihood to be of Norse origin.
Components of the paternal genotype expressed by Jim Retson in particular show a direct link with the
earliest modern humans in Europe with a mixture of eastern Indo-Europeans and Neanderthals
consistent with this view. Relatively recent history (800CE onwards) gives a clear idea as to how these
ancestral Retson Norseman arrived in England.
The Norse, of course, were the people known in the rest of Europe as the Vikings. Starting in
793CE Viking raiders began to pillage along the shores of present-day England, Scotland, Ireland, and
Wales. In 865CE there was a change in policy by the Norse and settlements were encouraged with the
area around Yorkshire falling first to settlement. These settlements were actively opposed by the AngloSaxons and efforts were made to eliminate or at least limit their spread. As a result, the main local of
settlement was to the north of England, although large areas of England came under Norse legal control
(the Danelaw).
The Anglo-Saxons of England vigorously resisted Norse settlements; they were more tolerated
by the Scots where Norse settlements acted to destabilize the Picts who were in control of much of
current Scotland. This favoured the Scots who took the opportunity to incorporate many Norse into
their groups although many islands in the Irish Sea and north of Scotland remained Norse for several
hundred more years.
In 1066CE, King Harold of England fought, and won, the last war against the Norse in what is
now York County but then had to move rapidly to the south to wage war on William of Normandy.
Arriving tired and ill-organized, Harold immediately went into battle and lost. Interestingly, William was
a duke in that part of France which had been ceded over to the Norse to prevent raiding on the French
Maternal (mtDNA) line:
The descendants of Grace Retson belong to mitochondrial haplogroup H11a1 (haitch eleven).
Female lines are notoriously hard to track historically. Firstly, the mitochondrial genome is very small as
compared with the Y-chromosome and so the “clock ticks slower”. Also, females have historically been
the objects of raiding parties, rape, and being used for cementing relationships between groups. As a
result, they tend to diffuse in location and show fewer subgroups.
That said, the H haplogroup is by far the most common mtDNA group in Europe and virtually all
Europeans belong to it or its derivatives (including H0, H0V, and V) or its subgroups. The particular
subgroup to which Grace Retson was derived is most commonly seen in Central Europe (the area of
Germany/Austria-Hungary). This area was a common cross-road through-out prehistory and the
chances exist that her male parent line included R1a and R1b lines. The high presence of Generalized
Western European in the DNA profile of Jim Retson would suggest that it was the R1a line, although
interaction of the R1a line with the I1 line in Scandinavia may also be the cause.4 If the mtDNA line
shows an R1a ancestry it suggests that her lineage is also Norse and included those that intermingled
with the I1 group in Scandinavia. If so, her ancestors would have arrived in England during the same
period as the Retson line and may have shared previous familial connections in the period between
(presumed) 865CE and the 1800s.
Specific Background for Jim Retson:
Scotland is a “melting pot” nation, with contributions from Germanic, Norse, Celtic, Roman,
Iberian and even African sources. The Retson genotype would represent a portion of this mixing.
As discussed, the Y-chromosomal information indicates a Norse background to the Retson
family. Knowing this opens up the possible origins of the name: for example, Rik was a Norse variant of
Erik and so the original name may have been Rikson (or Erikson). This may have been altered over the
years to become Ritson which is known to be the precursor of Retson.
In 1881 the distribution of the name Ritson was concentrated in Carlisle with lesser populations
in Durham, Newcastle, Lancaster, and Darlington5. All of these were areas of original Norse settlements
and indicates that there was very little movement outside of what had been Norse areas. At the same
time (1881), the name Retson was specifically a Scottish variant and was concentrated in Kilmarnock
with a spread to neighbouring Glasgow and Paisley. At this point, the population of Retsons in the
Dumfries area was too small to be noted.
By 1998 the name Ritson could be found in a much broader area and included new areas in
northern Wales and more southern England (Darlington, Lancaster and elsewhere). This later census
also recorded Ritsons now occurring in Dumfries in Scotland with the more northern Glasgow-area
Retson group having essentially disappeared.
Although there is a high proportion of the expected Anglo-Saxon (R1b1b2) background in the
Retson family background, there is also a fair bit of eastern European (likely from a R1a source via the
Norse) and input from Southern Europe and Iberia. These latter may have come from Roman sources
but may also have come from Celtic ones.
The Celts themselves have been subject to a major revision of thought recently. Previously
assumed to have been the earliest settlers of the British Isles who were forced to the extreme periphery
by the incoming Anglo-Saxons, it now seems that the Anglo-Saxons, predominantly hunters and herders,
were the original group and that the Celts were one of the last of the migrants to Europe (although of
R1b haplogroup origin as were the Anglo-Saxons). These late-comers were farmers and, unlike the
earlier I and R (Y-DNA) haplogroups which migrated through central Europe into northern Europe (with
some migration south during the ice ages), the ancient Celts are thought to have left the Middle East as
late as 5000CE and traveled a more southerly route through Italy to southern France. From there they
went to the more arable lands at the periphery of the lands occupied by the related Anglo-Saxon and
other Germanic peoples.
The arrival of the Celts in England about 4000CE had a revolutionary effect on populations
already in existence. In the case of the tribes in Scotland it brought the raising of grain and other crops
and greatly increasing the ability of the residents to support them. Because the Celts appear to have
taken a southerly route to the British Isles, it is possible that the southern European and Iberian
components of the Retson genome reflects an interaction with these late-arriving Celts.
The Retson genotype as evidenced by the DNA done by Jim Retson shows a clear linkage to its’
Norse origins. The Y-DNA haplotype is an ancient one and is typical of the Norse people. The DNA
analysis also shows the results of early interactions between modern Humans and the resident
Neanderthal which is largely absent from later migrants to Europe. Components of Central and Eastern
European genotypes are also common in the Norse and other Scandinavians and this supports the Norse
connection. As would be expected from a group who probably lived for a thousand years in a small
geographic area of north-western England, there is a heavy retention of these characteristics in addition
to an influx from later migrants typical of Anglo-Saxon sources and possibly Roman or Celtic
It is important to note also that these characteristics form major components of the current
Retson Genotype despite the fact that a recent maternal connection (the Cliffords) were likely strongly
Anglo-Saxon in origin, coming as they did from south-central England (in the area of Glouster). It
suggests that the direct maternal line (Atkinson) was also Norse in origin and retained many of the
ancient characteristics. This is supported by the mtDNA data which suggests a Central European lineage
to the maternal line, consistent with migration of an R1a or an R1b ancestor to the area of Scandinavia.
Short Course on Genetics
Inheritance of specific genes and sex:
Each of our cells contains 23 pairs of chromosomes (for a total of 46) held within the nucleus. One each of
these pair is derived from the paternal sperm cell and the other is derived from the mother’s egg cell. Together these
two sources make up the genetic profile held within each cell of your body. The exception to this statement are the
reproductive sperm and egg cells, where the genetic information varies from egg to egg and sperm to sperm.
During the formation of sperm and egg cells, only one chromosome of each of the pair is “chosen” and this
selection is random (with a 50:50 chance either one of the pair will be picked). These single chromosomes, grouped
together, form a complement of 23 individual chromosomes (haploid) in the resultant sperm or the egg and represent
a random mix of the ancestral paternal and maternal genetic information. Fertilization of the egg by the sperm
restores the full compliment. In a further mixing of information, a segment of one part of a chromosome pair can
“cross-over” and switch positions with the equivalent segment of its’ partner. As a result, the majority of an
individual chromosome may come from one ancestral line but contain genes from the alternate parental line. Most
often, however, there can be assumed to be an even distribution of chromosomes and therefore genes from both the
paternal and maternal cell lines, even with the mixing from the different sources.
The sex chromosomes in males represent an exception to the usual matched chromosomal pairs. In this
case, the X chromosome is more or less a “complete” chromosome while the Y chromosome is truncated and is
missing many of the genes normally present. Because all the somatic (non-sex) chromosomes are randomly mixed
with each generation, only the Y chromosome in the paternal line of descendents can be identified to pass from
generation to generation unchanged.
The absence of many genes on the Y chromosome (as compared to the X chromosome) results in many
genes on the X chromosome being the only version of what would normally be a pair. As a result these genes
become dominant by default. For example, the gene controlling the activity of the gene for baldness is on the X
chromosome. As a result, baldness is dominant in men (because there is no corresponding Y gene) but is recessive
in woman (where there would have to be two copies).
The Y chromosome is the only nuclear DNA that can be reliably traced from generation to generation and
therefore only the male line can be traced in this way. However, our cells contain another source of DNA outside of
the nucleus, in the cell cytoplasm. Small organelles called mitochondria (which are responsible for our aerobic
metabolism) arose from symbiotic bacteria and contain lengths of DNA material. All our mitochondrial DNA
(mDNA) is derived from the cytoplasm of the egg cell and therefore forms a method of tracing maternal ancestry.
With the sperm cell contributing an identifiable Y chromosome to the male line, and mDNA providing
information as to the maternal line, both the male and female ancestry can be followed. With each generation,
however, the female descendents will loose the male ancestry information of their mothers while male descendents
will not pass on their maternal information present in their fathers.
Genetic Drift and Evolution:
Chromosomes contain sets of genes. Many genes code for specific proteins and it is these specific proteins
which result in the characteristics that make up an individual. Some genes act to control other genes, turning them
either “off” or “on”.
Genes code for proteins by virtue of triplets of nucleotide sequences which specify a specific amino acid.
Chains of these triplet nucleotide sequences results in a chain of amino acids, and the characteristics of the amino
acids gives rise to particular folded shapes and sites of reactivity of specific proteins. Where the gene acts to control
other genes, the activity of one gene may affect an entire suite of characteristics.
An important feature of DNA (and proteins for that matter) is the feature of redundancy. Firstly, not all
combinations of nucleotide triplets code for a different amino acid, so the same amino acid might be coded by
different nucleotide triplets. Secondly, certain segments of a protein can have a change in the amino acid sequence
and this will have no effect on the activity of the protein. However, there are areas of a protein which are highly
protected as these are directly involved with the function of the protein. Changes here would render the protein
Another feature of DNA is that large sections of it seem to do nothing at all. Variously described as
“Useless DNA” or “Selfish DNA”, these segments have no apparent use and changes here have no effect on any
function of the cell.
All these levels of redundancy, ranging from (apparently) totally useless sections of DNA, through multiple
coding for amino acids by different triplet sequences, to the possible exchange of amino acids in non-critical areas of
a protein allows for changes in DNA that may have little initial outward effect. This is the basis for changes in the
DNA over time and the driving force in new mutations and evolution.
Mutations in the DNA sequence happen at a constant rate at random over the DNA strand. Where these
changes occur in important areas of the gene (usually because the resulting amino acid will render the protein
defective) are usually repaired by specific enzymes which are designed to look for these changes. However, many
changes are ignored, especially where the change occurs in redundant areas of DNA or where the change has no
detrimental effect.
The constant accumulation of changes in the DNA, while acting as a mechanism of evolution, also acts as a
“clock” to indicate how long two separate lines have existed since they diverged. Changes in DNA sequences form
variants which distinguish one cell line from another. 23andMe uses these changes in DNA sequences of specific
lengths of DNA, as well as amino acid sequences to plot the age of specific cell lines and therefore determine our
ancestry. In this way, for example, we find that the change in DNA that can be identified within a large number of
non-African humans has a separate change that defines the different haplogroups seen in the Middle East. Lines that
contain additional changes can be further defined. Each mutation can be localized to a point in time, and
examination of pre-historical human remains suggests where the change may have occurred.