A long-standing mystery of nature kind of bizarre pink marsupial embryo animal-like larvae outside the mother’s womb is curious in many ways.
Researchers at Duke University have found that the program of development of the embryo marsupial animal is performed in a slightly different order than the program of the embryonic development of virtually every second vertebrate.
"The legs are in a place for the entire period of development" - said Anna Kate (Anna Keyte), the researcher, Dr. Biology, Duke University, who conducted the analysis as part of his doctoral thesis. "They (the limbs) begin their development before almost any other structure of the body."
Previously, biologists have supported the idea that the development of the extremities triggered the initial development of other organ systems, but this analysis shows that the limb marsupial embryos begin to develop independently of the other bodies.
"Development is probably more flexible than we could learn otherwise" - said Kathleen Smith (Kathleen Smith) professor of biology. They observed animals were gray short-tailed opossums (Monodelphis domestica), living exclusively in Brazil and Bolivia, but, according to Professor Smith, the observations should be valid for any marsupial mammal.
To underdeveloped fetus was able to move through the mother’s abdomen from the delivery channel to the nipple, he needs a strong pair of front legs. For their creation, development program rebuilt so that the front legs beginning to form much earlier.
"Many of these genes have been included before you saw them in mice and chickens" - explained Kate. The researchers were also able to prove that the formation of the forelimb has been allocated by the body cells is significantly more than the normal development of the fetus in other vertebrates. Scientists were surprised also that the identification of the genetic program envisages the development of hind limbs as well as turned out to be previously enabled.
The genetic expression of sample sets, where each of the four limbs will be, but the forelimbs marsupials grow much faster than the hind limbs, as the fetus requires more cells to form the structures. Formation of the hind limbs as planned, but there is no material for construction.
Appears fetus from the womb of a mother with stalwart forearms, which include bones and well developed muscles, while the hind legs - small and underdeveloped.
Blind, without hair and with more immature brain, marsupial completely undeveloped fetus to live outside the mother’s womb. But the system is obviously a characteristic of marsupials.
"There are probably 50 explanations for why the marsupial animal embryo continues to grow outside the uterus, but none of them very convincing," - said Smith. However, it is abundantly clear that the external development of the embryo gives the female a lot more opportunities to control the playback. If conditions change or she lacks in food, the marsupial mother can easily complete the external pregnancy.
Original: Sciencedaily Translation: M. Potter