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In a bit of Twitter-ing exuberance, KTA/KTOB posted the following:

kta comment

In fairness to the organization, they were probably being more playful rather than practical in choosing to make that comment.

However, let’s set the record straight.

Oxbow and Paynter are by the same stallion, Adena Springs star Awesome Again, and they are out of mares who are full sisters: Tizamazing and Tizso (by Cee’s Tizzy out of Cee’s Song), making them full sisters to Horse of the Year Tiznow.

That is a fairly close relationship on paper. Their pedigrees look remarkably similar. But their genetic makeup may be — most probably is — quite a bit different.

Even with full brothers — by the same stallion out of the same mare — the resulting siblings share only 50 percent of the same genes on average. Yep, full siblings average out as “half-brothers and -sisters.”

Furthermore, for any pair of full siblings, there is exactly the same probability they share all the same genes as that they share none at all!

Well, those are long odds.

So, what about a mating like that which produced Tizamazing and Tizso, as well as their seven full siblings? From those nine foals, Cee’s Song produced four stakes winners, Tiznow (1997), Budroyale (1993), Tizbud (1999), and Tizdubai (2001). Tizamazing (2002) and Tizso (1995) were unraced and a nonwinner from two starts. Of the others, Tizsweet (1998) was third in her only start; Balboa Betty (1994) was a winner and eight times in the money from 15 starts for earnings of $38,120; and Ceebett (1992) was unplaced in a half-dozen starts for earnings of $1,050.

Cee’s Song produced these nine from her first 10 foals, and they include all her major performers. In addition to the excellent results of four stakes winners, the fact that two of the mare’s younger daughters have produced major stakes winners indicates that those also possess some level of important genetic material, even if they did not manage to show high class on the course.

The uncertainties of racing and training and working with horses guarantee that the racecourse test will have limits in selecting those horses that are most suited to being producers of the next generation.

Nonetheless, the racecourse test is the best and most obvious indicator.

And of the few genetic markers that we can verify by sight, four of full sibs were colts, and five were fillies, and that’s as close to 50 percent as can be attained with an odd number of foals.

In contrast, the mare — bred to a gray stallion — would on average have produced four or five gray foals but produced only three grays from the nine full siblings: 33.3 percent. Those three — Ceebett, Balboa Betty, and Tizsweet — managed one victory among them, and they are well below the norm of their siblings.

Does their coat color mean anything? Well, it means that they are gray.

Color, by itself, does not mean they are faster or slower. But it does give us a glimpse at the variability of traits and of the uncertain line of transmission of genetic material from one generation to another.

While parents give each offspring half their genes, the genes from previous generations are not distributed equally. Some foals will inherit more of their grandparents’ genes, others quite a lot less, and the results from more distant generations will be increasingly varied and minimal.

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