Cornwall has been a relatively isolated part of the British isles. Up to 1550 it spoke its own language, and had its own form of government and currency until the 1700s. Compared with other parts of Britain there has been little intermingling. Except perhaps from Devon, and a limited influx from Ireland and the continent, there has been limited in-migration until the present century. After 1850 however, when the great mines began to play out, there was a major exodus to other parts of the world where mines were to be found (Australasia, North and South America and South Africa,  the north of England and Wales). Because of the extended depression and enclosure of farmland, many agricultural workers and tradesmen also emigrated or went to London. Cornwall is said to have lost men at the rate of 1% per year for 50 years.

Cornwall had the largest known tin deposits in the world for thousands of years, and initially a great deal of alluvial gold. The first metalworkers to arrive in Britain were the Beaker People around 2500 BC, and they worked Cornish gold and tin extensively, while constructing a large number of ritual sites and burial chambers. A significant part of Cornwall's ancient Y-DNA stems from this very early period of settlement by Bronze Age intruders: there are many pockets of what appear to be early Bronze Age Y-DNA in Cornwall dating from 2500BC-2000BC during the goldrush.

After the Bronze Age finished, the demand for tin mostly dried up and Cornwall stagnated until the Industrial Era.  there are a few Iron Age intrusions from the Continent, a good quantity of Anglo-Saxon-Jute Y-lines from around 500AD, and a surprising amount of Danish/Viking YDNA from the Danelaw 900-1050AD. There appear to have been a few mediaeval Irish intrusions. 

These Beaker People have typical solitary burial crouched on their side, with a dagger and other metal grave goods, in a pit or sometimes within a dolmen or tumulus. They also seem to have been responsible for the many elaborate stone circle sites in Cornwall and nearby. Many items made of Cornish gold dating to the period have been found in Ireland.

THIS IS A SUBSIDIARY PROJECT OF THE CORNWALL PROJECT, A UNIQUE AND IMPORTANT RESEARCH DATABASE, AND SHOULD BE JOINED THROUGH CORNWALL 

Men in the CORNWALL project who are confirmed as meeting the following two conditions will be invited to join this Project

A. A confirmed Cornish paternal line ancestor, or have other good evidence of Cornish paternal descent (this will usually impley havin ga . 

B. They also have tested their SNPs to determine their deep haplogroup. This will usually mean having taken a Pack or Big Y test. A single 'deep SNP' is also sufficient.

We may relax these conditions for 

a) men who have a close STR match with a man who has taken a SNP test

b) men who have a Cornish surname and who match someone with a proven Cornish ancestor; or are in one of the distinctive Cornish DNA pockets we have identified. 

Make sure your earliest paternal ancestor is entered correctly, with parish first sighted (under your name>Genealogy)

Here are a few FAQ that may be helpful

http://www.familytreedna.com/groups/r-1b/faq#FYDNAtesting?