Crossing Salmons
There was a significant result from the crossbreeding that occurred in fall 1996: We were able to produce offspring within a single litter that could be classified into three different color pattern groups.A number of the baby boas in this litter were extremely pale in coloration. They lacked black scales entirely and were nearly pastel in coloration throughout their entire bodies, including the dorsal saddles, side blotches, belly regions and tail.
Individuals in the same litter as the pale babies exhibited the more typical salmon condition, which lacked the black borders on the dorsal saddle, except for the tail.
The third color pattern type was evident in a number of the pale individuals: there were substantial reductions in the amount of pattern, specifically in the size and shape of the dorsal saddles and side blotches. In these cases, the dorsal saddles looked like circles or narrow hourglass shapes. Furthermore, the irises and, sometimes, the tongue were modified and showed the salmon coloration. It was obvious to us that the animals expressing the extreme colors and patterns were likely genetically different from their first-generation salmon cousins.
We referred to the animals that had the most extreme appearances as "super salmon" and the more typical salmon animals as simply "salmon".
In these first crosses, approximately 50 percent of the offspring expressed the typical salmon appearance, 25 percent expressed the super salmon appearance and the remaining 25 percent had normal coloration and patterns (wild type).
In all of the aforementioned crosses, both males and females showed the salmon and super salmon condition; thus, we found no evidence that this trait was limited to one sex.
Next, we performed a single cross using two normal-looking littermates from a litter of salmon boas. This was done to determine whether or not the salmon trait might be heterozygous recessive. The nine offspring produced by the female were normal looking in appearance. Thus, this cross and the others described previously provided t;he first evidence that the salmon trait in boas was a dominant trait to the normal condition (equal to the wild type).
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