Detected body with the largest DNA world


09/10/2010

Scientists from Kew Jodrell Laboratory have discovered that a plant called Paris japonica, which is native to Japan, has the largest genome in the world. The size of its genome than the human genome, and broke the record of the previous record holder Grand protopter (Protopterus aethiopicus).

The results of the study were published in the journal Botanical Journal, which is published Lenneevskoe society.

This difference in genome size (amount of DNA) between plants and animals and fascinated at the same time has puzzled scientists since its opening in the early twentieth century. How and why they have evolved so differently, is still a mystery of nature.

In the world, there is a stunning variety in the size of the genome. The smallest genome (not including viruses and bacteria whose genomes are very small) has a parasite of humans and other mammals called Encephalitozoon intestinalis, the entire set of genes it weighs 0.0023 pg (picograms). Weight of the human genome is 3 m, that is 1300 times greater than that of the above parasite, but considerably less than in some of the animal and plant kingdoms.

Among animals, some amphibians have enormous genomes, but the record, until recently, was protopter Large (Protopterus aethiopicus) with 132.83 pg. Among the plants, the record for 34 years of keeping Grouse liseyagodny (Assyrian).

It was thought that we came up to the maximum size, which can reach genome. But this summer, a team of scientists from the laboratory Kew, discovered that the plant genome Paris japonica, native to Japan, 15 percent larger than those of the Greater and protopter is 152.23 m.

Ilia Leitch, a researcher at Jodrell Laboratory, said: "We were amazed to find that this little plant has such a large genome - it is so great that if it unravel, it would be longer than the tower of Big Ben in London.

"Some people ask, which means that such a large genome, and what is the difference between organisms with a larger DNA from the rest. Such organisms do have significant differences from the cellular level and ending with the body as a whole. Scientists have found that plants with larger genome are at greater risk of extinction and less adapted to living in the contaminated soil and to extreme environmental conditions that may adversely affect them in our difficult time. "

Another example of the importance and significance of genome size of animals and plants, is the fact that the larger the genome, the longer it takes the cells to copy the entire DNA code and separate. This means that the organism with a larger genome, it may take longer for the full life cycle, compared with organisms with smaller genomes. No coincidence that many plants growing in the desert and forced to grow rapidly after the rare rains have small genomes, which allows cells to divide rapidly. Organisms with large genomes grow much more slowly and can not compete in similar habitats.

The genome size correlated with the size of the cell nucleus where it is stored, because the more the DNA, the more he needs space.

Original: Sciencedaily


The volcano in Indonesia has made a new release of the ashes
Scientists have explained how insects breathe underwater
Natural herbicide helps turf grass to survive
Scientists: Sheep are much smarter than previously thought
First discovered pterodactyl egg with embryo