Difference between retroposons and retrotransposons
In contrast to
retrotransposons, retroposons never encode
reverse transcriptase (RT) (but see below). Therefore, they are non-autonomous elements with regard to
transposition activity (as opposed to
transposons).
Non-long terminal repeat (LTR) retrotransposons such as the human
LINE1 elements are sometimes falsely referred to as retroposons. However, this depends on the author. For example,
Howard Temin published the following definition: Retroposons encode RT but are devoid of
long terminal repeats (LTRs), for example
long interspersed elements (LINEs). Retrotransposons also feature LTRs and
retroviruses, in addition, are packaged as viral particles (virions). Retrosequences are non-autonomous elements devoid of RT. They are retroposed with the aid of the machinery of autonomous elements, such as LINEs; examples are
short interspersed nuclear elements (SINEs) or mRNA-derived
retro(pseudo)genes.[2][3][4]
Gene duplications
Retroposition accounts for approximately 10,000 gene-duplication events in the human genome, of which approximately 2-10% are likely to be functional.[5] Such genes are called
retrogenes and represent a certain type of retroposon.
Horizontal gene transfer
A classical event is the retroposition of a spliced pre-mRNA molecule of the
c-Src gene into the proviral ancestor of the
Rous sarcoma virus (RSV). The retroposed c-src pre-mRNA still contained a single
intron and within RSV is now referred to as
v-Src gene.[6]
^Makałowski W, Toda Y (2007). "Modulation of Host Genes by Mammalian Transposable Elements". In Volff JN, Schmid M (eds.). Gene and Protein Evolution. Genome Dynamics. Vol. 3 (3rd ed.). Basel: S. Karger. p. 166.
doi:
10.1159/000107610.
ISBN978-3-8055-8341-1.
OCLC729848415.
PMID18753791.
^Makałowski W, Gotea V, Pande A, Makałowska I (2019). "Transposable Elements: Classification, Identification, and Their Use as a Tool for Comparative Genomics". In Anisimova M (ed.). Evolutionary Genomics. Methods in Molecular Biology. Vol. 1910. Clifton, NJ. pp. 185–86.
doi:10.1007/978-1-4939-9074-0_6.
ISBN978-3-8055-8341-1.
OCLC145014779.
PMID31278665.{{
cite book}}: CS1 maint: location missing publisher (
link)