How to get offspring from two individuals of the same sex?
Daddy's kids: Mice don't need moms
"Popular Mechanics" by DailyTech publication:
Researchers Create Mouse With Two Fathers, Say Humans Could be NextBy combining the genetic material of two male mice, scientists have obtained healthy offspring that do not carry a single gene obtained from a female.
She became a surrogate mother in the full sense of the word.
On the left is a female with eggs bearing only "male" DNA (shown by the arrow) surrounded by her offspring;
on the right is the female, her offspring and the male who mated with her
A team of biologists from Texas, led by Richard Beringer, recently reported on such an "otherwise natural" achievement. They had to go "against nature" in another case: to obtain half of the set of chromosomes from the first male, they isolated connective tissue cells (fibroblasts) even at the time when he existed in the form of a fetus. So he could be said to have become a dad before he was even born.
Modern technologies allow manipulating fibroblasts with special ease. So scientists induced in them the property of pluripotency – i.e. the ability to transform into almost any other type of mature cells, and these pluripotent cells were cultured. During cultivation, something interesting and important happened – the cells lost the sexual Y chromosome.
Recall that mammals, in addition to the "normal" chromosomes, carry a pair of sexual ones: XX in females and XY in males. Accordingly, males are theoretically unable to produce offspring, otherwise it would carry a pair of YY, and would not have vital genes contained in the X chromosome. So the loss of one Y chromosome gave rise to a chimerical genome carrying one X chromosome - and not a single Y.
Then such XO cells were transplanted into the embryo of a female mouse, which, having matured, began to produce eggs bearing sets of XX and XO chromosomes. These females then mated with the second father, giving, among other things, offspring that did not receive the genes of their surrogate mother at all, but carried exclusively the genomes of two fathers.
According to the authors of the work (Biology of Reproduction, Jian Min Deng et al., Generation of Viable Male and Female Mice from Two Fathers), in principle, this approach can be developed even further – through the cultivation of eggs and sperm from stem cells of one male and their "self–fertilization" - until the offspring of one parent. We emphasize that this will not be the cloning familiar to everyone, namely the birth of new individuals.
Researchers believe that the technology can be invaluable for saving endangered species – for example, in cases where there is only one male individual left alive. It may also be useful for breeding new, even more productive breeds of farm animals. We hope that this will be the end of the matter, although members of the gay community are probably already discussing the prospects that open up before them…
Note that the birth of offspring without the participation of the father is not at all something unusual in nature. This process is called parthenogenesis, and we talked about it in the article "Undivided Motherhood".
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13.12.2010