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07-21-2005, 05:08 AM

Actually there have been a couple triple het ball pythons posted recently - but they where dominant type mutations where the hets are visible so it's sort of cheating. I think one was a spider pinstripe pastel (a visible het for all 3 morphs). This combo was probably made by breeding a double visible het like a pastel spider or a spider pinstripe to the 3rd visible het (pinstripe or pastel respectively). As long as all three mutations prove to be different genes on different chromosomes (I believe this to be proven for pastel and spider) this triple het combo could also be reproduced at the same 1 in 8 odds by breeding this first visible triple het to a normal.

I suspect the Honduran is het for three recessive morphs so probably produced by something like crossing a double homozygous recessive (perhaps snow - anerythristic and amelanistic) X a single homozygous recessive like a tangerine (at least I think that's recessive, not sure). While it’s harder to get the parents to produce known triple het recessives you at least get 100% triple hets out of the clutch where with the ball python dominant type example using het parents it’s only about 12.5% of the clutch that would be expected to be triple hets.

The distribution of offspring sex ratios brings up an interesting point. What if we find out later that something we assume is randomly distributed isn't? The near even long run split of all offspring in the population leads us to assume that the distribution is random. However, I've heard theories that the distribution for an individual male may not be random. The theory is along the lines that the farther the sperm has to swim the more likely male offspring are due to faster male sperm and the less distance it has to swim the more likely female offspring are due to stronger female sperm that can break through the egg wall quicker if they get there about the same time. This may well be an urban legend but it would be interesting to see a chart of a large number of sibling sex ratios to see if it's a nice normal curve with the high point at 50/50 or if it has peaks at either end that happen to balance the average out at 50/50 but indicate that individual parents tend to be skewed.

With snakes it's the female's genetic contribution that determines the gender of the offspring so it would be fun to look at the distribution in ball python clutches and see if it tends to peak at 50/50 or not. If not, it might get us looking into how the female makes her egg cells and might shed some light on the distribution of morph genes by the female too.

07-21-2005, 05:08 AM	#95
CornNut	Actually there have been a couple triple het ball pythons posted recently - but they where dominant type mutations where the hets are visible so it's sort of cheating. I think one was a spider pinstripe pastel (a visible het for all 3 morphs). This combo was probably made by breeding a double visible het like a pastel spider or a spider pinstripe to the 3rd visible het (pinstripe or pastel respectively). As long as all three mutations prove to be different genes on different chromosomes (I believe this to be proven for pastel and spider) this triple het combo could also be reproduced at the same 1 in 8 odds by breeding this first visible triple het to a normal. I suspect the Honduran is het for three recessive morphs so probably produced by something like crossing a double homozygous recessive (perhaps snow - anerythristic and amelanistic) X a single homozygous recessive like a tangerine (at least I think that's recessive, not sure). While it’s harder to get the parents to produce known triple het recessives you at least get 100% triple hets out of the clutch where with the ball python dominant type example using het parents it’s only about 12.5% of the clutch that would be expected to be triple hets. The distribution of offspring sex ratios brings up an interesting point. What if we find out later that something we assume is randomly distributed isn't? The near even long run split of all offspring in the population leads us to assume that the distribution is random. However, I've heard theories that the distribution for an individual male may not be random. The theory is along the lines that the farther the sperm has to swim the more likely male offspring are due to faster male sperm and the less distance it has to swim the more likely female offspring are due to stronger female sperm that can break through the egg wall quicker if they get there about the same time. This may well be an urban legend but it would be interesting to see a chart of a large number of sibling sex ratios to see if it's a nice normal curve with the high point at 50/50 or if it has peaks at either end that happen to balance the average out at 50/50 but indicate that individual parents tend to be skewed. With snakes it's the female's genetic contribution that determines the gender of the offspring so it would be fun to look at the distribution in ball python clutches and see if it tends to peak at 50/50 or not. If not, it might get us looking into how the female makes her egg cells and might shed some light on the distribution of morph genes by the female too.