In the mid-1990s, a new crawfish appeared in the German pet circle, the species is unknown, and its origin is unknown. The owners usually call it “Marbles Crawfish†according to the shell pattern. Gerhard Scholtz, a zoologist at Humboldt University in Berlin, Germany, tried to raise a marble crayfish alone. The spouse did not hide the seminal vesicles left over from the previous mating, but she continued to lay eggs and hatch offspring. Schultz's examination found that all of these offspring were female. This is the first crawfish known to be parthenogenetic!
The average length of the marble crayfish is 35 mm, and even individuals with a length of 103 mm have been found in the laboratory. Spawning, an average of 300 eggs per time. Female crayfish have an average of only 50 eggs. Even if you only put one in the wild, you can build a population that is better than the local crawfish.
Since the birth of mankind, men have played a decisive role in breeding the next generation, because the Y chromosome unique to their genes directly determines that the next generation of babies are male and female, so the Y chromosome has always been regarded as masculine. Representative of the gas. According to the Australian Interpretive News Network, the Y chromosome may be gradually disappearing! It sounds a little scary, the Y chromosome is gone, what will the man become in the future?
The Y chromosome may be a symbol of manhood, but this small chromosome does not symbolize strength. Although the Y chromosome carries the SRY gene that determines whether the next generation is the "key" of the boy (XY), at the same time it contains very few other genes, and the presence or absence of the Y chromosome seems to have little to do with the normal operation of life.
Pete Ellis and Dylan Griffin, professors of genetics at the University of Kent in the United Kingdom, analyzed the arguments for the disappearance of the Y chromosome. Scientists generally believe that the Y chromosome is gradually shrinking until it disappears. Women have two completely normal X chromosomes, while males have a normal X chromosome and a shrinking Y chromosome. If this deteriorating trend persists, it may be that after 4.6 million years, humans will not be able to maintain the Y chromosome.
Don't worry about the male compatriots. In fact, the scientific community is currently divided into "disappearing factions" and "reserving factions" on the question of whether the Y chromosome will really disappear. The "reservation faction" believes that the defense mechanism of the Y chromosome can save it. But the "disappearing faction" believes that all they do is nothing more than the dying struggle of the Y chromosome before it faces extinction.
In a recent study published in PLoS Genetics, the researchers partially sequenced Y chromosomes from 62 different males and found that there is a tendency for large-scale structural recombination to achieve "gene amplification." Gene amplification refers to the acquisition of multiple copies of a gene that enhance healthy sperm function and slow gene loss. That is to say, the Y chromosome also has a process of copying and pasting, so that the damaged gene can be repaired by copying the template.
The rotifer, a asexually propagated freshwater invertebrate, evolved to the asexual reproduction stage about 40 million years ago, and the eggs that were laid were all female offspring. There are many animals and plants in nature that are progeny through asexual reproduction, such as dandelion. Asexual reproduction is extremely common in invertebrates, such as aphids, but many fish and frogs also reproduce through asexual reproduction. The study found that these organisms are relatively low-level creatures, and the general evolution is still not perfect.
Most organisms in nature will evolve into sexual reproduction in order to adapt to environmental changes, so that this species can evolve new useful genes and eliminate bad or variant genes. Asexual reproduction of marble crayfish is a manifestation of species degradation, which means that sexual reproduction is more conducive to biological evolution than asexual reproduction. If human beings are in the process of evolution, don't worry that men will disappear.
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