Re: HYB: SA Modifier Gene?

In post #560, Walter wrote:
"Randy, this is interesting.  What you are saying here of your 
experience says [the SA trait is] dominant.  But others say it shows 
up in crosses between 2 non-SA.  This would not typical dominant 
behavior."

OK, I'm just babbling, and I don't really know beans about genetics, 
but here's what just popped into my head. (Sorry if someone brought 
this up already in a later post that I haven't made it to.)

What is the SA gene is a dominant modifier of some sort? If it's 
present, SA traits will appear, but if it's not present, SA traits 
won't? Or maybe this modifier works in tandem with another gene 
and/or in doses, as already suggested? Modifiers don't work alone, 
they work in combination with other genes.

I came to this thought through my "knowledge" of horse coat color 
genetics. For example, black is dominant. But if you stack a bay 
modifier on it, you get a bay horse (some shade of brown coat with 
black points (mane, tail & lower legs). Bay is a dominant modifier. 
However, to get a bay, the black gene MUST ALSO be present - that's 
where the black points come from. Without the black gene, but with a 
bay modifier, you get something else, depending on the other genes 
available for it to work with. Now, if you stack another modifier on 
a bay - a tobiano (paint) gene, you get a tricolor (bay) paint horse. 
Tobiano is also dominant. Remove the bay gene, and get a black and 
white paint. Remove the tobiano gene, too, and you're back to black. 
With the tobiano gene at least, I know that if it's there, you WILL 
see it expressed in the coat color. It does not work in doses. It's 
there or it's not. I learned this because my mare's sire was a bay 
tobiano, and her mother was black. Starfire is a bay, even though the 
tobiano gene is dominant. She inherited the bay modifier from her 
sire, but not the tobiano. 

Anyway, I don't know if this makes any sense or has any relevance 
here. Just tossing that "modifier" idea out there. If I'm way off-
base, please let me know, and don't feel bad about trampling my 
theory. It may well be that this is a "Well, Duh!" to those of you 
who actually know something about this stuff. I'm over my head here, 
I'll be the first admit it! But I am trying to learn! :o)

In serious jeopardy of pulling a brain muscle here,
Diana


 

------------------------ Yahoo! Groups Sponsor ---------------------~-->
Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark
Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada.
http://www.c1tracking.com/l.asp?cid=5511
http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/2gGylB/TM
---------------------------------------------------------------------~->

Yahoo! Groups Links

To visit your group on the web, go to:
 http://groups.yahoo.com/group/SpaceAgeRobin/

To unsubscribe from this group, send an email to:
 SpaceAgeRobin-unsubscribe@yahoogroups.com

Your use of Yahoo! Groups is subject to:
 http://docs.yahoo.com/info/terms/
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index