[Jacob-list] Horns and offspring

[Hobsickle at aol.com]

Horn number apparently follows a simple Mendelian dominant/recessive with 
multiple horns (more than two) being dominant.  This means that your 
two-horned sheep carry two genes for two horns.  Your four horned sheep carry 
either two genes for multiple horns or one gene for multiple horns and one 
gene for two horns.  The exception to this is if the horn bud splits in early 
development, but doesn't separate sufficiently.  In this case they may rejoin 
(fuse) and look like a two-horn sheep.  (Usually these "false" two horns have 
a seam running long-ways through the horns.)

The genetic control of horn shape and fusing (the later fusing that creates 
malformed horns) is apparently much more complicated.  It seems to be 
controlled by many factors and is not easily predicted.  (It has a lower 
"heritability" factor.)

Switching back and forth with rams probably won't increase horn problems, 
other than in two horned sheep their really isn't a fusing problem period.

-Dan


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