Cornwall

General project and portal
  • 954 members

FAQ

Who can join?

Membership now requires a verifiable Cornish ancestor - a specific individual born in Cornwall. For an autosomal test, the ancestor must be within the last five generations ie a Cornish g3gp, since there is a better than even chance of receiving no DNA from any ancestor more distant.  For a YDNA test or a mtDNA test, must provide a straight paternal line (no women) or maternal line (no men) ancestor, with date and parish of earliest record.   

NOTE - "looking for ancestors", "think I might be Cornish", "have Cornish admixture or matches", are not normally valid reasons to join.

Most of the members have now been screened for eligibility, but we reserve the right to remove anyone who has no verifiable Cornish connections, has not taken an appropriate  Y, mt or autosomal test, or breaks the Code of Conduct.

Can these conditions be varied?

In some circumstances, if someone has a particular investigative reason to join we grant provisional membership. For example, "I have circumstantial proof that my ancestor John White born 1827 was from Liskeard".  In a few cases, we have allowed men to join that have a Cornish surname and belong to a specific cluster we have identified as Cornish

What is DNA and the Y-chromosome?

DNA, the 'double helix' contains the building blocks of life in the nucleus of every cell. Human DNA has 26 pairs of chromomes. These randomly split and recombine when transferring to offspring, with the exception of the short, junk-filled Y-chromosome in males that is passed almost unchanged from father to son.

What are mitochondria?

Mitochondria are the small energy producing and regulating bodies within the cell. The numbers in each cell vary from zero (in red blood cells) to 4000 (in liver cells). they are passed only from the mother, so are useful in defining straight maternal lines. Also - there being so many per cell, it is easy to test very ancient DNA for mt and most early population movement studies of ancient populations employed it.  

What are STRs and SNPs?

STRs (Short tandem repeats) or microsatellites are short lengths of repeating DNA in inactive DNA. They mutate quite quickly because of slippage errors in the replicating process. The counts of repeats on a number of these STRs (eg 37 markers, 67 markers) give a unique family signature or haplotype, which will enable us to recognise paternal cousins out as far as 12 generations, sometimes longer.

SNPs (Single nucleotide polymorphisms) are mutations in a single DNA base. These are rare and occur mostly only once in the history of humanity. In the Y chromosome, they define the human Y-haplotree, which shows the unique line of descent from the first man to a tester.  

What kinds of DNA tests are in the project?
- Autosomal tests such as family Finder  test a selection of SNPs across all 26 chromosomes, excluding Y. Close relatives will have identical long strings of DNA in an autosomal test. The test can detect relatives out to about 6 generations, but sometimes further.

As well, short strings tend to be carried through a local population if it is 'inbred'. The presence of these strings, or of various SNPs,  can be used to determine to what extent someone has ancestry falling within the group. This is much more accurate if the two groups are widely separated.

- Y-STR   Tests of a smaller number of SNPs are not usually of much value. Only Y37 and Y111 tests are now available. Y37 is usually OK for men of the same surname, but may give matches with hundreds of other men. Y111 matches mostly only occur with related men of the same surname. The new BigY700 tests a total of 700 STRs, as well as most Y-SNPs.Women can take advantage by Y-testing a male relative with the same surname.

- Y-SNPs define haplogroups which can be progressively refined to lower levels, even down to a few generations before the present. They are best at defining relationships in the very long term, thousands of years, but they can also be used in the nearer term to define cousins.  The tests are BigY700, which will look at most of the SNPs of an individual (currently costs US$449), SNP packs, which test about 150 related SNPs for $99 or $119, and single SNP tests for $39. 

- mtDNA. Mitochondrial DNA tests determine the pure female lineage. Like Y, they define a mt-haplotree for women. The mitochondria are only small, so mutations give a very coarse screen with matches usually over a wide geographical area - while Y can give quite tight geographical clusters.  

What are NPEs?

NPEs (non-parental events) occur in countries with hereditary surnames when a son does not have the same surname as the father. This can be due to illegitimacy, adoption, name change and in a few cases, infidelity. They can be detected when people with the same surname in a particular location do not match each other on Y.

What are the subprojects?

We have structured the project to have two subprojects intended for research,  matching and general collection of Cornish DNA. Entry is normally through CORNWALL for people who meet the criteria and have done the right tests.

- Cornwall Advanced YDNA is for men of straight paternal-line Cornish descent (so usually a Cornish surname) who have tested their Y-SNPs with a pack or Big Y. This enables us to classify their DNA within the Y-haplotree as part of our project of defining Cornish YDNA, to say something about ancient origins and the period in which ancestors came to Britain or Cornwall, and to find clusters.

- Cornwall mtDNA is for people of straight maternal-line Cornish descent who have taken a mtDNA test. The mtDNA of members is curated and classified.

The main CORNWALL project is for general discussion of Cornish genealogy, history and DNA, including specials. The number of autosomal matches within CORNWALL has turned out to be a good measure of 'degree of Cornishness'. Older transfers from Ancestry or 23andme tests only gave a few hundred autosomal matches, and should now be re-done to obtain thousands of speculative matches. 

Do I need a family tree?

This feature is almost essential in locating autosomal cousins. It can be transferred from other testing companies as a gedcom file, or uploaded from a family tree program.

For Cornish ancestors of the individual family tree, parish of birth or marriage should be cited. We use this as our primary reminder of Cornish origins and '% Cornish".