Like a Virgin, Prasad, Aarathi [free children's ebooks pdf .TXT] 📗

babies. The three eggs that didn’t make it had collapsed early during the incubation, but they proved useful in providing embryonic material for genetic fingerprinting. Through such analyses, Flora was proven to be both mother and father to the surviving eight sons. Similarly, Sungai in London Zoo laid twenty-two eggs – two and a half years after her last contact with a male. Nearly eight months later, four of these eggs hatched, producing healthy sons. Sungai subsequently successfully mated with Raja, a male also housed at the zoo. Two months later, Sungai laid a second clutch of six eggs, only one of which hatched. Sungai has since died, but at Chester Zoo, Flora has been set up with Norman, a two-metre (seven-foot) male in whom the female has so far showed no interest whatsoever.

Komodo dragons and sharks aren’t like whiptail lizards; they aren’t all females, and they don’t behave – as has been said of whiptails – ‘like lesbians’. Flora the dragon and Tidbit the shark only experienced virgin births because they had no males to mate with. Theirs was an artificial situation, because they were living in zoos, but sometimes the situation in the wild isn’t altogether different. Poaching and human encroachment have decimated the population of Komodo dragons in the wild. Sharks are also increasingly overexploited: in the north-west Atlantic, there have been rapid declines in large coastal and oceanic shark populations – over a seventy-five percent decline, in fact, in the past twenty years or so.

Usually, hammerhead sharks in the wild have litters of around fifteen pups, and blacktips have four to six. Of the two sharks that were found to have had virgin births in captivity, both only had one pup. Having babies without a mate means that the offspring won’t enjoy as much genetic diversity as they would if they had a father’s genes too. And low genetic diversity is almost always a bad thing – something to be avoided in a population struggling for its existence; if every member of a family line has the same DNA, and that DNA is not well suited to the existing environment, it could spell disaster. Then again, a Komodo mother creating a male with which it can breed doesn’t appear to be such a bad option, when faced with extinction. And it’s not such a bad option to have just one shark daughter, instead of six, if the alternative is not reproducing at all.

Whether in situations where males are sparse, or simply as a matter of course, it is perfectly possible to create life from eggs alone – it’s a strategy that females of many species have long exploited. And indeed, parthenogenesis in animals has even been exploited, in a more domestic context, by us humans.

After the war, the US Department of Agriculture and British animal research units sponsored some interesting experiments with the ostensible aim of improving the efficiency and sustainability of animal husbandry. Then, in 1952, scientists at the Beltsville Agricultural Research Center in Maryland discovered parthenogenesis in turkey eggs. Immediately, selective breeding programmes were launched in an attempt to intensify the trait in certain lines of turkeys and chickens – it was the hunt for the ultimate breeder.

Those turkeys that showed the greatest predisposition for reproducing without sex were crossed, and were a runaway success – the Beltsville Small White breed. The percentage of virgin births in the turkeys increased from nearly seventeen percent to around forty-five percent in the space of a mere decade – a mote of evolutionary time.

Interestingly, parthenogenesis in the eggs of both chickens and turkeys was notable for the seeming lack of cell organization within the early embryos. A chaotic, multi-layered mess of cells would develop, whether it was grown in a hen’s oviduct or in an incubator. This made the scientists at Beltsville wonder whether an infection could have triggered the birds’ new mode of reproduction – an avian version of Wolbachia.

As a culprit, the researchers suspected a particular group of viruses, Rous sarcoma retrovirus, fowlpox virus, and Newcastle disease. Each of the viruses was found to enhance parthenogenesis; in other words, they appeared to stimulate the egg to develop into an embryo, an effect that, as with Wolbachia, persisted in the eggs of the daughters and granddaughters produced through virgin birth. Unlike with Wolbachia, however, virgin birth in the turkeys was not ‘curable’. If an already vaccinated turkey was infected with the fowlpox virus, the incidence of parthenogenesis in the eggs of that same hen increased markedly over the level recorded for her eggs before she was vaccinated – the opposite to what the scientists had expected.

Still, the data indicated that parthenogenesis could be boosted by selective breeding. The team could identify the ‘high-incidence’ turkeys, those recorded to have the highest predisposition for virgin birth, and keep the line going, without introducing sperm. The finding was backed by studies of fruit flies, among which it was observed that both males and females could transmit the parthenogenetic trait to their offspring. Through cross-breeding these flies, scientists increased the rate of parthenogenesis by around thirty-four times, compared to unselected fruit flies, in just twelve generations.

That, of course, leaves the question: if the birds and the bees can do it, why couldn’t we?

4

THE CONCERT IN THE EGG

The history of man for the nine months preceding his birth would probably be far more interesting, and contain events of greater moment, than all thethree score and ten years that follow it.

Samuel T. Coleridge, annotation to Religio Medici, 1802

It was March 1984. In a small town in Lesotho, a fifteen-year-old girl walked to a local bar to start work for the day. At some point during her shift, her new boyfriend showed up. Unfortunately, so did a jealous ex-lover – just in