Jumping genes
Jumping genes
Living in the same environment, one special type of arctic fish was capable of transferring its survival ability to another type. How this happened since these fishes never crossed and had offspring. In such a close environment, observations were easy and to surprise to all scientists, the answer was in jumping genes. These genes can change its place in genetic code in so many ways, apparently even some unknown ways.
Learning about jumping genes was interesting to all readers. It was always one of the most interesting parts of genetics. Here is a small review of known facts and a solid base for understanding new ways how genes could “jump”.
“A transposable element (TE, transposon, or jumping gene) is a DNA sequence that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. ... Transposons are also very useful to researchers as a means to alter DNA inside a living organism.”
Everything happens in living creatures and the first assumption is that jumping genes are one of the evolutionary drivers, for a species to adapt and survive. For example, thanks to these genes, species can change color to better adapt to a new environment and stay safe. This is why so many varieties of one plant species exist.
As for the historical facts: “Transposable elements (TEs), also known as "jumping genes," are DNA sequences that move from one location on the genome to another. These elements were first identified more than 50 years ago by geneticist Barbara McClintock of Cold Spring Harbor Laboratory in New York. “
Making a majority of the genome is an even more interesting fact, so now we can rely on our hopes to adapt and change even more than we did before. They are present in prokaryotes and eukaryotes.
“TEs make up approximately 50% of the human genome and up to 90% of the maize genome “(SanMiguel, 1996).
Types of Transposons
Making a majority of the genome, TE needed to be classified, and among many different divisions, here is one that separates TE into just two major groups, depending on their requirement for reverse transcription:
TEs that require reverse transcription (i.e., the transcription of RNA into DNA) to transpose and those that do not. The former elements are known as retrotransposons or class 1 TEs, whereas the latter is known as
DNA transposons or class 2 TEs. The Ac/Ds system that McClintock discovered falls in the latter category. Different classes of transposable elements are found in the genomes of different eukaryotic organisms
How do jumping genes pass from one individual to another?
Genetic information is shared via reproduction. This type of genetic transfer is also called vertical or passing traits “down”.
Another type of genetic transfer is horizontal DNA exchange and it does not include genes sharing tp the offspring.
“The article, “Horizontal transfer of BovB and L1 retrotransposons in eukaryotes,” is published in Genome Biology. The researchers from the University of Adelaide, led by David Adelson, Ph.D., professor at the University of Adelaide, department of genetics and evolution, found that horizontal gene transfer was much more widespread than was previously thought.” (2)
An interesting fact is that such a mechanism needs a transferring agent, for example, reptile ticks. This was represented in the work of Dr. Adelson, 2003 in the Proceedings of the National Academy of Sciences of the United States.
From these observations, it has become known that transferring species are often smaller insects like ticks, bed bugs, leech, locusts, and mosquitos; genes can be paste to their genome before jumping to another species genetic code. From a study of Dr. Adelson, we know there are millions of retrotransposon sequences in the plant, fungal, animal genomes. (2)
References:
1) https://www.nature.com/scitable/topicpage/transposons-the-jumping-genes-518/
2) https://www.genengnews.com/topics/omics/jumping-genes-hop-across-species-to-stir-human-evolution/
