...κ εκεί που χαρούμενη έψαχνα στο ίντερνετ τι θα κάνω στο Παρίσι, πού θα πάω κ τι καιρό θα κάνει, έπεσα πάνω στο Paris-Live! Coooooool, I thought...
Nice try κ με πρωτοβουλία της Ευρωπαϊκής Ένωσης κ με forum σε 5 γλώσσες! Καλό, ε?
Hi aaaaaaaaall!!!
Last night (huuuum...actually it was 6 o' clock this morning) I was studying Professor Campbell's lecture notes about "Sexual Differentiation"... I couldn't understand a single thing, so I decided to do some research in the internet (hell of a tool huh? I wonder how we could even cope without it). After a bit a came across Wikipedia's topic "Sexual Differentiation" and I couldn't stop scrolling down and reading...that was hell of a revelation!!!
As a matter of fact, becoming a male or a female is not as simple as I so far thought (and most of us still think)... Having XX(♀) or XY(♂) chromosomes in our genome is not enough! (although Autosomal and Genosomal chromosomes is basic knowledge, you can visit Wikipedia for a quick review).
A zygote (ie a fertilized egg, resulting from the fusion of an oocyte with a sperm) is undifferentiated during the early stages of its life. As a matter of fact, it is just a spherical mass of cells. During these first weeks of life, the fetus has no anatomical morphology nor sex specific hormones (like testosterone or oestradiol), because blood vessels are not yet developed for the hormones to circulate in the bloodstream. Only karyotype screening can distinguish the male from the female.
But even so, the are males with XXY, XXXY or even XX genotype and females with XXY genotype (that usually have specific behavioural activity like elevated criminal behaviour). What happens in that case? There is a specific gene, the SRY, located on the short arm of the Y chromosome, encoding the SRY protein (or else TDF = Testes Determining Factor). TDF's job is to induce differentiation of cells (specific cells of the undifferentiated cell mass) into testes. Other genes (that encode for specific proteins/factors/hormones) are also responsible for the formation of male gonads (testes). Though, there are no genes or hormones that induce formation of female gonads (ovaries).
So...to produce a fully reproductively functional male of typical morphology and behaviour, two processes are needed: Defeminization (suppression of female typical morphology) and Masculinization (production of male typical morphology)!
To sum up... you "able-bodied" guys are soooooo lucky! Even one small mutation in one of the genes that are responsible for the development of your "thingies", could simply turn you into females, as female is the default developmental pathway during embryogenesis!!!
(Photos: http://www.istockphoto.com/index.php, last accessed 15-1-2007 & http://www.channel4.com/index.html?hpos=logo, last accessed 15-1-2007)
Ομολογώ ό,τι στο χωριό μου είχα να πατήσω το πόδι περίπου 15 χρόνια... Παρόλο που όσο ήμουν μικρότερη (huuuuuum...μέχρι Γυμνάσιο) πήγαινα κάθε καλοκαίρι με τις ξαδέρφες μου για πολλές ημέρες κ με τον παππού μου κάναμε εξερευνήσεις σε δασάκια, στα γύρω βουνά κ σε κοιλάδες...
Once more the one to blame is boredom...
