What do you think of the English expression of "She has farming in her blood." which is usually said of someone who is a farmer and whose parents were farmers, etc. "She is a farmer." would not indicate how good she is at it. While the first expression doesn't necessarily mean she has chosen that as her profession, but if she did she would be good at it. Thank you for this link by the way: http://nualeargais.ie/gnag/bi_ina.htm
Do any Irish expressions tend to indicate that not only do they have that position, but they are good or skilled at it or were raised by people in the field who may have helped them to understand that field better?
The FGB entry for dúchas (birthright, heritage) shows a number of different examples that convey the same meaning as "in their blood" - it's also how you refer to a "native speaker" of a language.
Rud a bheith sa dúchas agat, to have something. in one’s blood, to have a natural aptitude for something
Dúchas ruda a bheith ionat, to be hereditarily inclined towards something
Thug sé leis ó dhúchas é, he inherited it; it comes naturally to him
Tá an ceol inti ó dhúchas, she is musical by nature; she comes of a musical family
Tá dúchas le mairnéalacht aige, he has a bent for seamanship; he comes of a seafaring people
Tá dúchas le bainne aici, (of cow) she is of a good milking strain
Tá an teanga ó dhúchas aige, he is a native speaker of the language
Tá dúchas a shean ag fás leis, his hereditary instincts are being aroused
Éireannach, fear uasal, ó dhúchas, a born Irishman, gentleman.
The NEID only has one example of "in their blood" in that sense, and gives two suggestions, the first using dúchas, the second being more of an example of béarlachas, just a literal translation.
"music is in her blood" -
tá an ceol sa dúchas aici
tá an ceol san fhuil inti
Could someone please tell me if this summary is correct:
Is feirmeoir í == She is a farmer (simple, basic way of saying it)
Feirmeoir atá inti == She is a farmer, not primarily, but among other things OR She recently became a farmer
Feirmeoir is ea í == She is a FARMER (with emphasis on farmer)