What are the postive and negative effects of transposons?

NEGATIVE EFFECTS:

There are multiple negative effects of transposons on phenotypes:

• If transposon insert themselves into a coding region or into a regulatory sequence, they will most probably render that gene inactive.
• Upon leaving a site, the gap that is left by a transposon will need to be repaired, this repair, often, will cause genetic mutations in the original gene and render it inactive.
• Sequences that are repeated multiple time leads to unequal crossing over and chromosomal abnormalities.
• A number of diseases in the genome have been linked to transposons, such as Hemophilia A and B Porphyria. Severe Combined Immunodeficiency (SCID), predisposition to cancer and Duchenne Muscular Dystrophy.

Despite these negative aspects there can be positive impacts of transposable elements:

POSITIVE EFFECTS:

• Sometimes non-transposons, coding, DNA gets carried along with mobile elements during transposition; this would lead to the duplication of beneficial genes or the creation of new genes.
• Sometimes genetic mutation caused by transposons may modify regulatory sequences and this could change the pattern of expression of gene produced, which could lead to some new beneficial characteristics.
• The rate of transposition has actually been observed to increase in some cases under the conditions of stress. This higher rate of transposition could cause genetic mutations leading to new traits, which would allow an organism to adapt better to changing environmental conditions.
• Transposons have also come in handy as tools for scientists who wish to create transgenic organisms or modify an organism DNA for research purposes.