Reptile & Amphibian Forums

I was looking for information about a previous post of mine below about male snake sperm production (in which I found out I was wrong, by the way) and ran across some interesting items.
First off I was wrong about male snakes constantly producing viable sperm throughout the season. The cooler periods are what helps to create viable sperm. Similar to mammals which keep their testes at a cooler temp to produce sperm.
That said, I found an article about a researcher that came into his lab and found his female timber rattlesnake with a newborn in the cage. What was amazing was that the female was a study animal that had not been in contact with a male for over 10 years. At first they assumed a record sperm retention but after examining the DNA discovered that the genetics were virtually indentical. A few minor signatures were missing but thats the only difference.
That means that reproduction occured without fertilization. (parthenogenesis).
Now I am extremely curious to find out more about any other occurences of this being documented. I found on other document that said that western fence lizards in an all female population had exhibited this too.
Has anyone run across anything relating to this phenomenon. If so please share.

Arik

Plus I learned a new big word (parthenogenesis) lol

I kept looking and found some more articles but I'm done typing so here's a link. lol

http://home.pcisys.net/~dlblanc/Parthenogenesis.html

Arik

This article is even more informative and deals with a boid.

www.albinoburmese.com/parthenogenesis.pdf

Arik

Just sharing some of my new found education. lol

Parthenogenesis has been found more and more with snakes as we research it. It is interesting though because it is not a clone as in lizards. What happens is due to the way snake chromosomes work, offspring can only be male (making it impossible to be a clone of the mother). There are quite a few cases of this happening and funny you mention this but this Trimeresurus albolabris owned by Rob Charmichael I took a photo of has one babie with her that is a suspected parthenogenic birth. A while ago I was so fascinated in the differences in parthenogenesis in higher vertibrates and how "christ like" lol it is in snakes I read quite a bit on this. I can get into more detail if you like.

This was brought up a while ago in the venomous forum. Here is a good post.

"I just wanted to clarify a few of the things that have been brought up in response to parthenogenesis in snakes. First of all, the type of parthenogenesis here is completely different than that which occurs in lizards (formerly Cnemidophorus). The baby snakes are not clones of the mother. In fact, it is thought that it is almost impossible for female snakes to be produced, as I will explain later. The sex chromosomes in snakes are termed Z and W, and in this case the females have the differing lineup (ZW) whereas the males will display the paired ZZ condition. If eggs try to combine as WW, the egg will not be viable. During meiosis in the female snake, the original cell divides once after each chromosome pair line up in the middle of the cell, then retreating to either side. The sex chromosomes split, so each subsequent cell that is produced contains a duplicate copy of half of the female's original DNA (and either a Z or W sex chromosome). These cells then divide again, leaving a total of 4 germ cells each containing one half of the female's original DNA, and each germ cell containing one sex chromosome. In total, 2 germ cells are produced containing Z sex chromosomes, and 2 contain W sex chromosomes. One of the germ cells will contain most of the fluids from the original cell, and become the egg. The other three cells become what is known as a polar body and are generally reabsorbed in the female's reproductive tract. Sometimes, however, it is theorized that one of these polar bodies (typically the one that is produced alongside the egg) will be absorbed into the egg and fertilize it. Thus, this union would either end up with a sex chromosome combination of ZZ or WW (non-viable). The resulting offspring would be male! Also, this neonate would only contain ONE HALF of the female's original DNA, duplicated. I don't know if it is possible for the egg to combine with one of the polar bodies created from the other original half of the female's DNA - I suppose it could be possible? It is far more likely that the resulting offspring would be either males or essentially unfertilized ova (WW sex chromosome combinations that failed). Hope this clears things up for you RE: the parthenogenesis condition. "

Is this a capabilty in all snakes or just select species. For example condas. I've found documentation on 4 species that it has occured. These species were completely different i.e. timber rattlesnakes compared to burmese python. It seems logical that if those two completely different species have the capability then all reptiles, snakes specifically, would posess it.

I also came across a research paper about reptiles being able to select which sperm fertilizes the ovum. It was done on some lizard in arid africa that mated with multiple males and somehow they 'proved' that the female could select the most dominate males to actually fertilize the ovum. Considering how condas naturally breed (multiple males) this was a subject that held my attention. I haven't found any supporting documents to confirm this study though. Still looking.

Thanks for your input.

Arik

There would be variation onto what species are capable of parthenogenesis since snakes have a descent variation in evolution. Also, there is a lot more being found out with types of hermaphroditism in some snakes as well. Just think..1 in 100 human births is sexually different than standard male or female and interesex syndroms are much more known than they are talked about look into klinefelters, androgen insenstivity, 5 alfa reductase, turners (while not hermaphroditic it is still a sex chromosome syndrom), etc.. It would be interesting to see where research leads. Jeff Corwin just had an episode on about an island snake species (forget what it was) where females have one hemipene that is not functional. This is general as a species but I would be more than willing to bet there are a ton of snakes ou there where things like that occur often at random.

there is a bunch of smart cookies in this forum and it surprises me that none of them wanted to add to the parthenogenesis discussion. Oh well.

That's one of the reasons I posted. The forums been getting dead and I was trying to start a good thread. lol.
Oh well, better luck next time.

Thanks for responding to the pic.

Arik

there doesn't seem to be a lot of interest in the subject. I have heard of a few cases with crotalids, but never in a boid species until now. Thanks,

Kelly