IN NOVEMBER the world鈥檚 first cloned baby could be born, if reports this week are to be believed. But cloning experts are horrified and say that even if the baby is healthy, the mother could be at a high risk of a rare invasive womb cancer.
Once more, Severino Antinori, the maverick Italian fertility expert, is at the centre of a controversy with his colleague Panos Zavos of the Andrology Institute of America in Lexington, Massachusetts. The pair vowed to clone a baby by the end of 2001.
Shock waves reverberated around the world last week at the report that one of Antinori鈥檚 patients is pregnant with a clone. According to Gulf News, he told a meeting in the United Arab Emirates that 鈥渙ne woman among thousands of infertile couples in the programme is eight weeks pregnant鈥�.
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Details are scarce, however. Neither Zavos nor Antinori would confirm or deny the news when 快猫短视频contacted them. But Giancarlo Calzolari, a journalist with Il Temponewspaper in Rome and a friend of Antinori鈥檚, claims Antinori told him that the news is true and the clone is of an 鈥渋mportant, wealthy personality鈥�. Calzolari was also told that the cloning procedure was performed in a Muslim country.
Whatever the truth, condemnation came thick and fast in the wake of the news. Most of Antinori鈥檚 critics warned that cloning is very inefficient鈥攐nly 1 to 6 per cent of cloned embryos survive to birth, and many die soon after, often from malformations.
鈥淚 am appalled that these people are attempting to produce cloned humans,鈥� says Rudolf Jaenisch, a cloning expert at the Massachusetts Institute of Technology. 鈥淎ll evidence indicates that most clones die early鈥攖he lucky ones鈥攁nd the rare survivors may have serious abnormalities which may become apparent only later.鈥�
But amid fears for the clone itself, worries have emerged about the future health of the mother. Richard Gardner, an expert on early mammalian embryo development who chaired Britain鈥檚 Royal Society鈥檚 working group on cloning, says that the mother could be at risk from choriocarcinoma, an unusual form of cancer unique to humans.
The cancer develops from the trophoblast, the part of an embryo that invades the womb wall and develops into the placenta. Though the causes are unknown, poorly regulated genes controlling the growth of the placenta seem to be the key.
Animal experiments have shown that these genes remain switched on in cloned embryos when they should be silenced by a chemical masking process called 鈥渋mprinting鈥�. This means that important genes linked to the development of the placenta could go into overdrive, accelerating its growth and posing high risks to mothers.
鈥淭he human has the most invasive placenta to start with,鈥� says Gardner, a zooloiogist at the University of Oxford. 鈥淚f placental growth goes awry, there鈥檚 a greater propensity for this problem to emerge in humans than in other animals.鈥� He admits that while the risk is only theoretical, people have paid far too little attention to it, focusing instead on the fate of the clone itself.
Barry Hancock, director of a clinic at Weston Park Hospital in Sheffield that specialises in the treatment of trophoblastic cancers, agrees that abnormal imprinting in the genes of cloned human embryos may increase a mother鈥檚 risk of the disease. 鈥淏ut it鈥檚 a theoretical risk,鈥� he says.
Whatever the dangers, many people doubt Antinori鈥檚 claims and want to see some solid proof. 鈥淚t鈥檚 very difficult to know what, if anything, is true,鈥� says Harry Griffin, head of communications at the Roslin Institute near Edinburgh where Dolly the sheep was cloned.