I'd have to have more samples from different sons and daughters of his. It could be many factors. One of the differences is size, as mr.is only 44 pounds. Machabear is as big as Machobuck, so I'd have to see which ones are the same in Machabear and MR. And use deductive reasoning. The other one is color as machabear is yellow and Machobuck and mr.Machobuck are dark red. As for now I'm thinking the very first allele is color since both MR. And the original share that allele and Machabear does not. The last one may be size, as Machobuck and Machabear share it and MR. Does not. But those are just guesses, I need more samples off Machobuck offspring to be able to back those claims. The short answer is genotypes. The two letters are DNA markers. Each DNA marker or allele pairs contain an allele from each parent. If the offspring does not have at least one letter or marker from the sire at each allele pair then he is disqualified as the parent.