As we all know transposable elements are unique segments of DNA that move around to different sites in the genome. Due to this transposition, they can end up any where in the genome. The relocation of these segments bring up a few thoughts and concerns in the scientific community. The research that is continuously being done on these sequences shows that they bring forth diversity in the organism. At the same time, these transposable elements result in various diseases through the process of mutations that occur when these elements move into another region of the genome. Even though the TE (transposable elements) tend to be neutral in response, they have a great influence on regulating genes and their function. There usually tends to be multiple copies of these TE and a good portion of the genome is made up of them.
A type of transposable element called retrotransposons found in eukaryotic cells, transpose through using RNA intermediate structures. A sub-unit of these retroviruses are LTR (long terminal repeats), that leave transposable sequences when cleaved out of the genome. These TE that are left behind bring a great amount of diversity to the genome through expression of gene regulation. Other research shows how transposable elements influence early development in the embryonic stage. Retrotransposons that are responsible in that stage called LINE-1 retrotransposons translocate into the regulatory sequence to control expression during that time.
Work cited:
ReplyDeleteBiemont C.,Vieira C.(2006).Junk DNA as evolutionary force.Nature,vol443(5),521-524.
In your blog you stated that the TE are also known as the jumping gene and move throughout the genome, what would you consider to be the pros and cons of this event taking place other than diversity through mutation?
ReplyDeleteAlso, as a suggestion, instead of the actual source of citation, I would recommend including a hyperlink for those who want to look the article up themselves.
From what I have read, transposable elements are greatly being used as tools in genomic studies, for example an transposable sequence is inserted into a region into a genome where then it is able to duplicate or is used to generate chromosomal deletions. I’m not quite sure about the cons fully but I know that they are rather large and therefore not preferable to work with when doing fine detail analysis.
DeleteSo you've only briefly addressed the title of your post: how do these "junk" genes contribute to organismal diversity? What differences can they make in phenotype?
ReplyDeleteFrom what I understand, by the mechanism of translocation and duplicating its self into other locations in the genome, these TE are able to bring more diversity into the genome. For example in maize, there are these sequences called helitron rolling-circle elements that act like transposable elements. They are responsible for copying gene segments into new locations, which develops diversity in the maize genome. The outcome of the genomic diversity results in the different colors of maize.
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