Open thread: parthenogenesis in Komodo dragons

This article originally appeared on Geek Feminism.

A baby Komodo dragon born by parthenogenesis, photographed at Chester Zoo (CC BY-SA 3.0, Wikipedia user Neil)
A baby Komodo dragon born by parthenogenesis, photographed at Chester Zoo (CC BY-SA 3.0, Wikipedia user Neil)

What the hell. It’s geeky. And this is a fairly new (published 2006) finding about komodo dragons. To quote from Wikipedia:

On December 20, 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and 7 of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified that Flora had never been in physical contact with a male dragon. After Flora’s eggs’ condition had been discovered, testing showed that [London Zoo dragon] Sungai’s eggs were also produced without outside fertilization…

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove that Flora’s unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop.

The Nature article is Phillip C. Watts et al (2006) Parthenogenesis in Komodo dragons, Nature 444, 1021–1022 (21 December 2006), doi:10.1038/4441021a.

This is an open thread, for a discussion of biology geeking, great nerdy events and, of course, anything else you want to discuss!

Menstrual geeking: getting started

This article originally appeared on Geek Feminism.

I was surfing around on Vagina Dentata which I stumble across periodically (most recently in our last linkspam) but have not quite got to feed-reader-adding yet. This is poor form I admit”Š”””ŠI’ll go right off and add it after writing this”Š”””Šbut does mean that I can enjoy a number of posts at once. Today I spent some time on periods. Periods. PERIODS. P.E.R.I.O.D.S. and Time to talk periods and thought other folks of the menstruating kind and/or the geeky kind might enjoy a bit of related geekery.

My official menstrual cycle education essentially boiled down to, if I recall correctly, that there was a time when one bled, a longer time when one didn’t and that at some point during the longer time ovulation occurred. And there were was certain amount of practical information regarding pads and tampons, which largely came down to a few diagrams and “beware Toxic Shock Syndrome”. Only in my mid-twenties, looking only to fill, I think, idle geek time, I found out about the follicular phase and the luteal phase, about fertilisation taking place in the Fallopian tubes and implantation occurring only around a week later, about the fairly short lifespan of the ovum and the fairly large corpus luteum cysts that ovulating women develop each cycle. (I had an early ultrasound of my current pregnancy, while the cyst was still presumably secreting progesterone, and it was a fairly big black circle on my ovary.) As best I understand, and I’m very much a layperson when it comes to the science of menstruation, Wikipedia’s article on the menstrual cycle is a good place to start reading for your menstrual geeking initiation.

I learned this when on the recommendation of another woman geek I picked up Toni Weschler’s book Taking Charge of Your Fertility. It’s a Fertility Awareness guide, about using a combination of basal body temperature, cervical mucus and cervical position to identify fertile times in your menstrual cycle in order to either get pregnant or avoid it. (This is not necessarily a religiously inspired practice, and it’s more effective as a contraceptive than you’d expect: much of the dubious reputation of cycle-based methods of contraception comes from use of strictly calendar based methods. Fertility Awareness requires a fairly good working knowledge of the signs and the use of either barrier methods or abstinence at fertile times though, with failure modes you can imagine.) I can’t get as excited about the idea of taking my temperature every morning of my fertile life as Weschler can, and I’ve never charted a cycle to the extent that would satisfy a Fertility Awareness educator, but I have tracked my temperature through a couple of cycles in order to observe the basic signs. I’d recommend this book if you’d like to do some serious observing of your menstrual cycle from, as it were, the outside.

Vagina Dentata also has a promising pointer to the re: Cycling blog of the Society for Menstrual Cycle research, and you might be interested in (note: photos of cervixes at link… as you’d expect) the Beautiful Cervix photos taken throughout various people’s cycles.

If you have a geeky interest in menstruation and related things, what are the coolest facts you know, and what are your favourite sources of info?

Someone is going to make a bingo card about my notes to commenters some day, aren’t they? Today’s note is: remember that not all women menstruate, and not all people who menstruate are women.