Almost all snakes reproduce sexually, with the participation of female and male. Only certain species are capable of parthenogenesis, i.e. the reproduction is not transmitted sexually, and from unfertilized eggs without the participation of a male. There among the snakes, as a rare exception, and true hermaphrodites, i.e. individuals who are simultaneously female and male. Such exceptional case was recorded on the small island of Queimada-Grande, South America. There were found the snake, dubbed the island bothrops, among which, in addition to ordinary females and males, meet bisexual individuals who make up the majority of the population. These individuals are females, while the ovaries are the male copulatory organs and Mature testes. Such individuals may in some cases play the role of females and to breed, and the males are fertilizing other females (ordinary or hermaphrodite). The existence in the population of the island bothrops such unusual females is so efficient, the need for normal males has dropped, and their share in recent years has declined.
The female from the male in the overwhelming majority of snake species difficult to distinguish. The serpent the visible Continue reading
In the legends of ancient China tells the story of that dragon once there was a huge sea snake or a giant boa constrictor, swollen from the sea water in the Yangtze river.
Live large Boas and Kharkov zoo. Although to see their usual Kharkiv is unlikely. For the past four years as the entrance to the terrarium of the zoo is closed — emergency building on the brink of destruction. The roof of the cage, consisting of concrete slabs started to crumble. And simple repair in this case is not enough.
Once there was an aquarium for fish the local waters, says head of the Department of amphibians and reptiles of the zoo Olga Kalinovskaya, and when in 1995 marking the centenary of the zoo, was transformed into the current terrarium. Now the zoo management plans to restore the aquarium, and over it to build the pavilion-a terrarium. It remains only to find the money to build.
Thus it happened that now to exhibit a collection of snakes for the zoo anywhere. New housing received only crocodiles, lizards and small amphibians in the premises of the recently renovated monkey house. The rest live in various closed the eyes of the visitors spaces.
In Kharkov zoo today is home to 20 snake species, only about 200 individuals creeping. All of them are tropical snakes that were bred in captivity.
Creeping the oldest inhabitant of the zoo — a female Continue reading
Found a gene that determines, will become a gamete sperm or egg
Japanese genetics found in the DNA of fish unusual gene that determines it, will the sex cell sperm or egg, and changed his work so that in the ovaries of female fish began to form spermatozoa and in the testes of males of the egg, according to a paper published in the journal Science .
“We knew that gametes can turn into sperm and ovum, but no one has suggested that these cells in the vertebrate animals have a special gene”switch” that determines their fate – to become a sperm or egg. Our results indicate that the cell is able to go all the way. This is a very important and unexpected discovery” – quoted by RIA “Novosti” scientist Minoru Tanaka from the Institute of General biology of Japan in the city of Okazaki.
Tanaka and his colleagues made this unusual discovery, watching the development of germ cells in testes and ovaries rice fish-oriii (Oryzias latipes). During maturation of sperm and egg cells, researchers monitored changes in the level of activity of different genes, trying to find the differences between future male and female reproductive cells.
The attention of scientists was attracted to gene foxl3 – “archival copy” of the gene foxl2, which is responsible for growth of eggs and maintaining Continue reading