Neither women nor men can procreate with each other. For homosexual couples this means that A biological child of both parents can give. In mice, researchers are working on it, the gender borders.
Now it is possible for the first time, to breed from cells of two mouse females healthy offspring. Reporting Bao-Yang Hu of the Chinese Academy of Sciences and colleagues in the journal “Cell Stem Cell”.
The mice with two mothers would have been sure to get a healthy offspring, the researchers said. The success rate was still low. Only 14 percent of the Attempts viable mice.
The researchers have bred in addition, mice from two male cells. These survived only a few weeks.
mouse offspring from two fathers.
hammerhead sharks can. without males reproduce
The scientists began by investigating in more detail why the same-sex reproduction in mammals is so difficult and what distinguishes it from other species Some reptiles, amphibians and fish, for example, hammerhead sharks and Komodo dragons, need doubt no paternal genetic material to replicate.
The Problem in mammals: In the Embryo, either the Version of the father or of the mother is in some genes active, never both. Experts call the genomic imprinting. The genetic material comes from two females, or two males, is not working this System correctly. The result is severe developmental defects, which can mean the death of the embryo.
In previous studies had tried to researchers have already been to remove these formative genes from ova. When you Merge with a second female cell then automatically the gene variants would be formative, the idea. However, the resulting mouse embryos had severe damage. Healthy young, it was never.
210 Attempts, 29 living mice
Hu and colleagues refined this approach now. You used to be female, embryonic stem cells, and the contained as the Egg and sperm cells only half of the normally existing chromosomes and DNA. Experts speak of haploid cells.
Using the Genschere Crispr/Cas9, the researchers from the cells removed portions of three formative Genetic material. The cells injected in the ovum of a mouse, the genetic material into an Embryo. From 210 of such embryos 29 live mice originated. They grew up normal and had later self-offspring.
The second mouse generation
The breeding of mice with two fathers was even more complicated. In the haploid stem cells, the researchers distant seven formative Gene segments. The modified cells were then combined with the sperm of another male mouse in an egg. eight. From this before the nucleus had been with the female genetic material removed.
surrogate mothers carrying the embryos. These, however, survived for only about 48 hours.
To be unsafe for use in people
in Principle, the method could also be transmitted to humans. It is major ethical and technical hurdles remain, however.
So other genes are, for example, in genomic imprinting involved than in the case of mice, the researchers argue. The risks of life of disabled babies, or babies with severe development would damage to the world, are therefore much too large. Zhi-Kun Li, who was also involved in the study, warns, therefore, against excessive expectations.
The value of the experiments, the researchers have yet to understand why for the reproduction of mammals is always a female and a male is needed.