Of course, if ERV sequences have a function, then God may have had a functional reason for initially placing them at the same chromosomal location in separately created species. He also may have had a functional reason for designing a system to favor the insertion of certain ERV sequences at certain loci. In other words, maybe retroviruses are a corruption of an original complex system that was designed to facilitate diversification within kinds (per Wood). What was designed as an “altruistic genetic element,” now shows only vestiges of that original benevolent purpose. In that case, the fact ERVs (and other transposons) now have mostly deleterious effects is because the original system has degenerated as a result of the Fall, not because they arose by random processes.
In that regard, it is interesting that, in addition to evincing certain functions, some ERVs (and other transposons) also exhibit an insertion bias. Perhaps this is another remnant of a more finely tuned system. Sverdlov writes:
But although this concept of retrovirus selectivity is currently prevailing, practically all genomic regions were reported to be used as primary integration targets, however, with different preferences. There were identified ‘hot spots’ containing integration sites used up to 280 times more frequently than predicted mathematically. A recent study of the de novo retroviral integration demonstrated also preference for scaffold- or matrix-attachment regions (S/MARs) flanked by DNA with high bending potential. The S/MARs are thought to be important functional sequences of the genome that anchor chromatin loops to the nuclear matrix subdividing the genome into functional domains. They often neighbor regulatory elements involved in gene expression and DNA replication.
A cautious generalization from these findings could be that although TEs can integrate into many sites and may prefer non-coding regions, the de novo integration is frequently targeted at the sites in the vicinity of functionally important elements like transcriptions start points or origins of replication. (Sverdlov, 3.)
In addition, LTRs associated with HERVs frequently coincide with genes. This raises the possibility that they are somehow related functionally to those genes.
We found frequent coincidences in positions of HERV-K LTRs and mapped genes on human chromosome 19 where the situation with mapped genes is slightly better. Although it would be premature to interpret this result as the indication of the regulatory interplay between closely located LTRs and genes, still some the the coincidences seem interesting. Most striking is the frequent coincidence of the LTRs with Zn-finger or Zn-finger-like genes scattered all over the chromosome. . . . Among other interesting coincidences, the LTRs were often detected in the vicinity of a number of genes (
RRAS, EPOR, JAK3 etc.) implicated at different stages of Jak-Strat signal transduction pathway. The frequent coincidences of the LTRs with the genes of similar or concerted functions might suggest either functional involvement of the LTRs in the expression of the genes or their evolutionary relations. (Sverdlov, 4.)
- A Critique of ''29 Evidences for Macroevolution'' - Part 4 -
