# New paper: how starting sequence can shape RNA evolutionary possibilities **URL:** \ **Category:** AWG Discussions\ **Created:** [September 15, 2026, 8:53pm UTC](https://awg.osdr.space/t/new-paper-how-starting-sequence-can-shape-rna-evolutionary-possibilities/4604 "2026-09-15T20:53:55Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![mrtirum2](https://sea1.discourse-cdn.com/flex001/user_avatar/awg.osdr.space/mrtirum2/32/972_2.png) [@mrtirum2](https://awg.osdr.space/u/mrtirum2)\ **Post date:** [September 15, 2026, 8:53pm UTC](https://awg.osdr.space/t/new-paper-how-starting-sequence-can-shape-rna-evolutionary-possibilities/4604/1 "2026-09-15T20:53:55Z")
Our new paper in the _Journal of Molecular Evolution_ asks whether different RNA starting sequences have equal access to nearby structural possibilities. **Key takeaways:** - Not all starting sequences are equivalent - some have access to richer nearby landscapes of potentially foldable variants. - Certain nucleotide positions act like **“anchors”** , with much larger effects on predicted foldability than other positions. - Combinations of favorable positions can produce **greater-than-additive effects**. - These broad patterns remained even when G-U wobble pairing was excluded. - The results suggest that **where evolution starts in sequence space can influence what becomes accessible later**. - This may have implications for the **RNA world and origins of life** , where early sequence history could have shaped later structural possibilities. - The study is computational and based on predicted secondary structures, so it provides testable hypotheses rather than direct experimental proof of function. More broadly, the idea may be relevant beyond RNA: complex search spaces can be highly uneven, with some variables and combinations having much greater leverage than others. **Paper:** _Positional Anchors and Cooperative Retained-Position Sets Define Non-Equivalent RNA Sequence Landscapes - Journal of Molecular Evolution_ > **[Positional Anchors and Cooperative Retained-Position Sets Define...](https://link.springer.com/article/10.1007/s00239-026-10345-0)** > > Different RNA sequences do not have equal access to nearby structural sequence space, but how strongly local sequence neighborhoods depend on starting-sequence identity and individual nucleotide positions remains unclear. Here, we compared the fully... [@MicrobesAWG](https://awg.osdr.space/groups/microbesawg)