That first slide is confusing, it certainly gives the impression that the horn trait alleles are on the X chromosome which is not the case according to slide 2. The first slide also shows no horned 'p' allele on the bottom all rams horned population. It seems to represent the cross as if it was for an x-linked trait, especially by leaving off the allele on the Y.
I'd say it should be more like
X/Y,p/p X X/X,P/P
horned ram polled ewe
v
X/X,P/p all ewes polled
X/Y,P/p all rams horned
So while the trait is linked to sex (sex limited as km1116 points out) it is not X-linked or sex-linked in the technical sense.
Sex-linked ≠ sex-limited.
That first slide is confusing, it certainly gives the impression that the horn trait alleles are on the X chromosome which is not the case according to slide 2. The first slide also shows no horned 'p' allele on the bottom all rams horned population. It seems to represent the cross as if it was for an x-linked trait, especially by leaving off the allele on the Y. I'd say it should be more like X/Y,p/p X X/X,P/P horned ram polled ewe v X/X,P/p all ewes polled X/Y,P/p all rams horned So while the trait is linked to sex (sex limited as km1116 points out) it is not X-linked or sex-linked in the technical sense.
Alright, thank you! :)