Interesting collection of maps at Project Mapping including UK-wide rail maps in Welsh. Very nice to see names such as Bryste, Manceinion and Llundain appear. though there are a few errors such as "Amwythig" for Shrewsbury when it should be "Yr Amwythig", Glasgow's name is not translated to Glascoed, Yr Efrog (York) is missing the definite article ... the definite article being very important in some placenames...regrettably its use seems to be falling with names such as Y Barri just being written as Barri on some roadsigns etc.
Same applies to the use of soft mutation (treiglad meddal) when you see abominations such as Croeso i Porthladd Abergwaun, when it should be Croeso i Borthladd Abergwaun.
Mind you, could be worse as found in this article.
Picture copyright BBC
As for genetic mutations, I'll find some genetic maps and maybe even some lingustic mutation maps...