Mallett Surname DNA Study — Background Information

Purpose

Why a DNA study?

"Genealogy by DNA" is very likely to become an indespensible tool of the Genealogist in the not too distant future. It is not meant to replace traditional methods of research, but rather to supplement them. It can:

  • Confirm that 2 family groups are related where the traditional paper evidence is suspect or weak.
  • Establish a timeframe in which to look for traditional evidence when this is not well understood or unknown.
  • Suggest the type of records that one might seek to prove a relationship: if the DNA evidence shows that the common ancestor for two family groups lived prior to the time when BDM records were systematically kept, for instance, the only evidence available might be a will.
  • Prove that a relationship exists even though no traditional evidence has been found, or is likely to be found, because the records needed to prove the relationship in the traditional way simply do not exist.

Goals

  • To identify the haplotype of a given branch of the Mallett family, while at the same time looking for similarities with other branches of the larger Mallett family group.
  • To identify a timeframe in which a common ancestor existed for apparently different branches of the family, using currently accepted Y-DNA mutation rates and years per generation, and to develop an ancestral haplotype for those groups.
  • To prove, or disprove, as the case may be, the theory held by many Mallett researchers that all Malet/Mallet/Mallett/Malettes etc., regardless of the particular spelling of their name today, and whether or not their forebears came from England, France, Switzerland, Belgium, Italy, Spain, or elsewhere, descend from the Norman Barons known to have carried the Malet surname in Normandy, France, at the time of William of Normandy's Conquest of England in 1066 and before. See "1066 and all that" for more information on that topic.

Further Reading

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Definitions

  • Haplotype:

    A unique genetic pattern of an individual or shared by a small group of individuals, pointing to common ancestry in the relatively recent past, used to differentiate families from one another within a genealogical timeframe.
  • Haplogroup:

    A genetic pattern shared by a large group of individuals, pointing to common ancestry far back in time, used to determine the common ethnic and geographical origins of the group.
  • TMRCA:

    "Time to Most Recent Common Ancestor" - measured in generations or years, dependent upon a given rate of mutation for the markers tested, and an average value for years per generation. See "Methodology", below.
  • Genealogical Timeframe:

    Generally the period of time, historically, that surnames have existed, which is anywhere from 500 to 1000 years ago, roughly. The Malet name has been known to exist for 1000 years or more.
  • Transmission Event:

    1 transmission event is counted for each marker tested, in every generation in the male line, i.e. when a father has a son and passes on the Y chromosome.
  • FTDNA:

    "Family Tree DNA", the DNA service provider for this and many other Surname DNA studies.

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Methodology

The study involves an analysis of the Y-chromosome, carried only by males, that is passed from father to son (along with the surname) with, usually, no change. There are known mutation rates for the Y chromosome though, and this allows one family to differentiate itself from another over time.


Mutation Rates

There has been and continues to be a great deal of discussion on the topic of mutation rates for the markers on the Y chromosome. There have been 4 major studies done to date:

  • Heyer et al (1997)
  • Bianchi et al (1998)
  • Kayser et al (2000)
  • Holtkemper et al (2001)

The generally accepted rate is 1 mutation per 500 transmission events (.002), because this is the average of the values found by the first 3 studies. The 4th study, however, determined that the rate was 1 per 250 transmission events (.004). Most researchers feel that .002 is too low, and .004 is too high, so perhaps the actual rate lies somewhere between the two. In fact, Doug McDonald (thanks to Terry Barton for making this available on the web) has done his own analysis of FTDNA's 25 marker test (the one we have used), and concluded that the average mutation rate for those 25 markers is .0028.

Suffice to say that the jury is still out - but hopefully a more precise value will be available in the fall of 2004. FTDNA has undertaken a new mutation rate study based on their large and ever growing database of results. Their goal is to determine an actual mutation rate for each of the markers that they test, something the other studies did not do.

Until a more definitive rate is available, we will use 3 different rates (.002, .003, and .004) when making calculations, and present our conclusions as a range of values.


Calculating TMRCA

One of the most useful aspects of a DNA study is to estimate the general timeframe in which a common ancestor for two otherwise unrelated families might have lived. If this falls within an acceptable genealogical timeframe, then the two families can be considered to be related in a genealogical sense, i.e. they have the same surname, and they probably have a common ancestor within the timeframe that the surname is known to have existed.

This can be looked at in two ways:

  • Generations
  • Years

Generations
Generations per Mutation
Markers 12 25 37
R
a
t
e
.002 42 20 14
.003 28 13 9
.004 21 10 7
The table at the left shows the number of generations represented by a single mutation when x number of markers have been tested. It is given by the formula:
"1 / mutation rate x number of markers tested". FTDNA offers 12, 25, and 37 marker tests, so each is represented in the table. As discussed above, we are using 3 different mutation rates in our calculations, so a value is provided for each mutation rate and each number of markers tested.

Years

The 3 tables below show the number of years corresponding to the number of generations calculated in the table above, relative to 3 different factors representing the number of years represented by an average generation, i.e. 20, 25, or 30.

12 Markers
Years 20 25 30
R
a
t
e
42 840 1050 1260
28 560 700 840
21 420 525 630
25 Markers
Years 20 25 30
R
a
t
e
20 400 500 600
13 260 325 390
10 200 250 300
37 Markers
Years 20 25 30
R
a
t
e
14 280 350 420
9 180 225 270
7 140 175 210


How Relationships are Determined

A "transmission event" occurs for each marker tested each time a father has a son and the Y chromosome is passed on. There is no way to predict when a mutation will occur, but given enough transmission events we can reasonably predict that one will have occurred somewhere along the line, based on the values presented in the above tables.

If there are very few mutations, e.g. 2 participants differ by 2 markers in a 25 marker test, then we know that the two individuals are very closely related, and can predict the general time frame in which their common ancestor must have lived, simply by multiplying the actual number of mutations by one of the factors from the above tables, and dividing by 2. We divide by 2 because the above factors represent rates for 25 markers per generation, but we have 50 markers between the 2 individuals for each generation.


Example 1 - Confirming the Paperwork

A given group has three participants, and each of them tested for 25 markers. There are 3 separate lines, all stemming from a common ancestor, each separated from one another by 9 generations, representing 27 transmission events. There is one mutation among the 3. The model predicts:

  • 25 markers x 27 transmission events x 0.2% = 1.35 mutations.

We can therefore accept that the one participant whose haplotype differs from the other two by one count on one marker (one mutation) is still related to them, because the actual number of mutations is less than what is predicted by the model, even at its most conservative mutation rate.


Example 2 - Predicting a Timeframe for a Common Ancestor

5 participants have tested for 25 markers and are divided into 2 family groups according to the results of the test. Group 1 has one mutation among 3 participants. Group 2 contains 2 individuals who are a perfect match. Each group has a documented genealogy going back 10 generations.

Since 2 of the 3 participants in group 1 match, we will consider their result to be the haplotype for that group, essentially ignoring the mutation in the 3rd person's line. There are 6 differences between the haplotype for group 1 and the haplotype for group 2. We will compare one set of markers for each group, so we have 50 markers to consider, which represents 50 transmission events per generation. We will use median values for mutation rate (.003) and years per generation (25) in our calculation of TMRCA:

  • Generations per mutation = 1 / 50 x .003 = 6.66
  • TMRCA (in generations) = 6.66 x 6 = 40
  • TMRCA (in years) = 40 x 25 = 1000

Further Reading

DNA Studies underway, tutorials, and links to other resources:

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How to Join

A surname study for the surname Mallett and any conceivable alternate spelling has been established at: Family Tree DNA.


Basic Requirements

Sex:

Each participant must be male.

Surname Variations:

Each particpant must carry some variation of the Mallett surname, including, but not limited to, the following:

  • Malet
  • Mallet
  • Mallett
  • Mellett
  • Mullett
  • Mallott
  • Maleth
  • Mallette
  • Malette
  • Maillet
  • Maletto
Ethnic Background:

Completely and utterly unimportant. We are aware that there are people carrying a variation of the Mallett surname who are of French, English, Spanish, Italian, and African origin, and perhaps more. All are welcome. We are in fact quite keen to have representation from all of these groups in the study.


Cost

The Mallett Surname DNA Study unfortunately does not have any funding, so each participant must be prepared to pay for their own test. The options are as follows (all prices quoted are US Dollars):

  • 12 Marker Test: $99.00
  • 25 Marker Test: $148.00
  • 37 Marker Test: $189.00
  • 67 Marker Test: $269.00

The 25 marker test is recommended because it provides much higher resolution than the 12 and is much more useful in terms of being able to establish meaningful genealogical relationships, but the 12 marker test can be helpful to establish whether or not one matches any of the current participants, and it can be upgraded to 25, 37, or 67 markers later:

  • Upgrade 12 to 25: $49.00
  • Upgrade 12 to 37: $99.00
  • Upgrade 12 to 67: $189.00
  • Upgrade 25 to 37: $49.00
  • Upgrade 25 to 67: $148.00
  • Upgrade 37 to 67: $99.00

Sponsorship

If you are interested in our study and are perhaps unable to participate yourself, or are able and would like to assist others to participate, please consider becoming a sponsor. Sponsors can make arrangements directly with FTDNA to purchase a test for a specific individual, or to pay for a portion of a test, while the participant (or another sponsor) pays the balance.


Contact

If you would like to join our study or become a sponsor, or would just like more information, then please contact the study coordinator Bob Mallett by clicking on "EMAIL" below.

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Author:

Bob Mallett

Ottawa, Ontario
Canada

Last update August 19, 2007