Even as the rest of an animal's genetic code can mutate, retroposons and their locations are stable, making them a reliable indicator of relationships between animals.
The scientists found all marsupials shared the same 10 retroposons, meaning they all descended form a common ancestor, reports The Courier Mail.
The concerted evolution of retroposon subfamilies provides evidence that subfamilies do not arise independently.
Genomes of the other mammals, including human, tree shrew, bat, and rabbit (traditionally classified in a sister taxon to rodents), apparently do not contain this retroposon. Although the human Alu and the B1 SINE elements are both derived from the 7SL gene, lack of an amplification product in the human supports the conclusion that these retroposons evolved separately as distinct SINE families.
Use of the short retroposon B2 in the study of phylogenetic relationship in rodents.
coypus by reviewing the current data and establishing a case for the analysis of specific genomic retroposons, molecular fossils of the nutria's evolutionary descent.
MOLECULAR FOSSILS: RETROPOSONS AS PHYLOGENETIC TOOLS
Another type of genetic analysis involves the use of retroposed genetic elements (retroposons; reviewed in Deininger and Batzer 1993).
(47) Bejerano, Lowe, Ahituv et al., "A Distal Enhancer and an Ultra-conserved Exon Are Derived from a Novel Retroposon
"; Kamal, Xie, and Lander, "A Large Family of Ancient Repeat Elements in the Human Genome Is Under Strong Selection"; Lowe, Bejerano, and Haussler, "Thousands of Mobile Element Fragments Undergo Strong Purifying Selection near Developmental Genes"; Gentles, Wakefield, Kohany et al., "Evolutionary Dynamics of Ttransposable Elements in the Short-tailed Opossum Monodelphia domestica."
Molecular evidence from retroposons
that whales form a clade within even-toed ungulates.
Alu elements are 300 bp retroposons
(RNA-mediated transposable elements) that are amplified in the primate genome by the process of retrotransposition (retroposition) (Figure 1).
Some repeats (called SINE and LINE elements) in human chromosomes still seem active, others (LTR retroposons
) are nearly inactive, and yet others (DNA transposons) are totally inactive.