Know the difference!
Although both words have similar meaning in the general context, there’s a fundamental difference between nucleic acid hybrid and chimera. In case of the hybrid, two or three strands are linked by the hydrogen bonds, following the rules of complementarity. Being the central property of any nucleic acid, the hybridisation emerges in numerous instances, be it DNA double helices or microRNA/siRNA silencing complexes.
On the other hand, a chimera is a covalent fusion of distinct nucleic acids. Here, there are two cases: they can differ only by the origin (such as fusion genes, coming from separate chromosomal loci or donor species), or be composed by chemically different nucleotides (e.g. RNA-DNA chimera). Both kinds of chimeras can form naturally – by the chromosomal rearrangements and viral insertions, or as short-lived RNA primers linked to the newly synthesized DNA strands during genome replication. Additionally, the research from 1999 shows that the RNA part of a RNA-DNA chimera can stabilise the central reaction intermediate in homologous recombination, and such chimera was successfully used in targeted gene repairin the mammalian cell-free system.
- Targeted gene repair (RNA-DNA chimera)