It is the other way around. The Sumatra lost the FM genes but retained the GF modifier. And yes GF stands for gypsy faced. I hate that term as it seems racist to me. It is the modifier that causes birds to have black faces. It is found in many breeds including Hedemora and Birchen Marans.DC it's just that I've read on different fm forums your mentioning the GF gene....looking at the Sumatra except for the Gypsy Face..is tis anaha moment here??!!..GF...means Gypsy Face? ...if so how could hyperpigmented face eventually wipe out suppress pretty much the FM gene expression in the Sumatra breed ?
I don't know why this didn't add up earlier.
I have the 90% AC hybrids..eggs coming in a few days...I paid the huge extra for 'priority express'..hope for better shipping handling this way and some good fm birds from these.
They always say don't count your chickens before they're hatched...hahaha...will I ever learn?
Some Cemani breeders are working on reintroducing the GF modifier in their Cemani lines by crossing them to Sumatra and the crossing back several generations. The very best FM birds have two copies of the FM gene plus the GF modifier.