When the original Celts of Ireland actually arrived is unknown, with suggestions having been made of between 100 and 5000 years B.C. from linguistic and other evidence. The late Neolithic Beaker folk introduced their cultural advances possibly from the Low Countries or from Iberia; this resulted in key changes and Irish becoming a unique Celtic language. Recent evidence shows a huge number of Irish men have the R1b DNA marker with similarly high percentages also found in other modern 'celtic' areas on the European Atlantic coast, including the Basque region. The first known farmers in Ireland or Britain landed in Kerry c.4350 B.C. but the incidence of their DNA markers is now very scarce, the R1b marker replacing it c.2500 B.C. This coincides well with the arrival of a dominant Beaker culture, including the introduction of copper mining and metallurgy in Kerry.