Saturday, April 1, 2006

Parthenogenesis



The big surprise – Parthenogenesis!

The problem that Drs. Chizar and Smith had was a number of odd occurrences either in their labs or other locations/situations that they were familiar with. It was the same “problem” that has been recorded multiple times in populations of western fence lizards (believe this is correct) that were entirely female. The problem that had plagued scientists was how these animals were able to produce living offspring without the presence of a male of the species. This is known as parthenogenesis and was thought to be limited to this one species. (Of course, this was convenient because it didn’t disturb the current balance of their knowledge, which had reptiles reproducing using the same genetic model as mammals.) This way of looking at reptile gender encoding was totally disrupted when Dr. Chizar entered his lab one morning to find a female Timber rattlesnake, Crotalus horridus in her enclosure with a new baby rattlesnake. This female was a research animal and had not been with a male of her species for roughly 10 years or more!

At first, it looked like a record for reptile sperm retention. DNA samples were taken along with finally determining that the offspring was male, and the results shook the scientific world to its reptilian foundation. DNA samples from the mother and offspring looked basically identical except for a few minor coding signatures that were totally missing. Along with Dr. Smith, samples of other occurrences of the same thing were compared with quite similar results. Parthenogenesis in snakes had been confirmed!

The problem this now presented was figuring out exactly how this phenomenon happened. They had to look again at a number of offspring, a couple of which had survived and a good number that had been stillborn, and recheck the gender. It began to appear that all viable offspring had in fact been male with no complete female offspring produced.

If more information on this event, and other similar events, can be found, we will post it here as soon as possible.


I'm almost certain this little peach (Crotalus horridus - Timber rattlesnake) isn't bound for my collection even if it doesn't need a male to reproduce.





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