[quote:89c4b856be]If indeed the York boar had a black carrier, then our york litter would all carry the black line, correct?
No, this is not correct. I'll explain, Traits are controlled by genes, and genes have different forms which are known as alleles. For example; the gene for coat color can have two alleles. One white allele and one black allele. In higher organisms such as pigs there are two alleles on each chromosome pair. So, one of each of the above alleles (black, white) can be found on a chromosome pair. Meaning the animal can carry both the color black and the color white. An example of this would be your boar who carries both the gene for black and the gene for white.
Dominant genes mask or cover the presence of recessive genes. Capital letters are used to designate dominant genes. A recessive gene is one that is over ridden by a dominat gene. For a recessive trait to appear (phenotypically) the animal must be homozygous ( have two of the same gene- one on each chromosome) for that characteistic to appear.
If you bred a PURE york to your non pure york this is what you will see
Pure York: White: WW
Cross Boar: WB : white/black
So you will have half the litter that will be carriers of the black gene and the other half will only carry the genotype for the color white. Also, to clarify, BOTH white and black are dominant traits. That is why you get blue butts in the first place, due to codominance or incomplete dominance which is a blending of traits which causes the color roan/ blue.