Rat genetics

All other topics relating to rat care which have not been covered above
Post Reply
Bobsmith
Posts: 2
Joined: Wed May 18, 2016 5:39 pm

Rat genetics

Post by Bobsmith » Wed May 18, 2016 5:54 pm

Hello, I am new to this forum and have some questions regarding the genetics of fancy rats.
I have been looking into the various colours and genes of rats due to a college assignment which requires Agouti coat alleles to be discussed. The task in hand requires me to show a cross between two fauns which subsequently carry the agouti gene. However I am having issues when trying to determine if non-agouti 'aa' (black) is more or less recessive than the ruby eyed allele 'rr'. I understand that the agouti allele is dominant over all others.

Any answers at all would be much appreciated as I know very little about fancy rat genetics! :( :D

User avatar
cyber ratty
Fancy Rats Team
Posts: 5897
Joined: Thu Jul 07, 2011 8:47 am
Location: South Cambridgeshire
Contact:

Re: Rat genetics

Post by cyber ratty » Wed May 18, 2016 7:35 pm

a is just as recessive as r... (I'll use the UK terminology)

A- rr = topaz
aa rr = buff

A- R- = agouti
aa R- = black

Bobsmith
Posts: 2
Joined: Wed May 18, 2016 5:39 pm

Re: Rat genetics

Post by Bobsmith » Wed May 18, 2016 9:53 pm

Thank you! Thats exactly the information I required :D So would the topaz be classed as expressing incomplete dominance or co-dominance? I would assume incomplete dominance as the topaz appears to be one coat colour?

User avatar
cyber ratty
Fancy Rats Team
Posts: 5897
Joined: Thu Jul 07, 2011 8:47 am
Location: South Cambridgeshire
Contact:

Re: Rat genetics

Post by cyber ratty » Thu May 19, 2016 8:51 am

The two genes are quite separate so I don't understand the question really - i.e. when two independent genes are expressed at the same time, they combine, you don't usually get one being dominant over the other (an example of that would be c, where an albino rat, cc, will not visibly display any other colour genes, so c could be said to be dominant over other colour genes).

An example of a co-dominant or incomplete dominant gene would be the h locus.

HH = unmarked (assuming no other marking genes, lol)
Hh = berkshire
hh = hooded

I should add that I'm not fully familiar with all the terminology relating to genes, but I know a fair bit about the genes for rat varieties.

Post Reply

Return to “Other care”