Evolution: new forms require new genes (Evolution)

by David Turell , Wednesday, May 12, 2021, 23:54 (1289 days ago) @ dhw

An obvious requirement according to these papers:

https://evolutionnews.org/2021/05/did-the-origin-of-animals-require-new-genes/

"Recent studies show that many genes typically associated with metazoan functions actually pre-date animals themselves, supporting functional co-option of ‘unicellular genes’ during the genesis of metazoans.

***

"However, the role of genome novelty in animal origins has not been fully evaluated. We hypothesize that genomic novelty had a major impact in this transition, particularly involving biological functions which are hallmarks of animal multicellularity (gene regulation, signalling, cell adhesion, and cell cycle). Here we apply a comparative genomics approach using sophisticated methods, newly developed programs, and a comprehensive taxon sampling. The reconstruction of the ancestral genome of the last common ancestor of animals shows a set of biological functions similar to other eukaryote ancestors, while revealing an unexpected expansion of gene diversity. These analyses also highlight 25 groups of genes only found in animals that are highly retained in all their genomes, with essential functions linked to animal multicellularity.

***

"Thus, the first animal genome was not only showing a higher proportion of Novel HG [homology groups], but these also perform major multicellular functions in the modern fruit fly genome. The implication is that the transition was accompanied by an increase of genomic innovation, including many new, divergent, and subsequently ubiquitous genes encoding regulatory functions associated with animal multicellularity.

https://www.nature.com/articles/s41467-018-04136-5.pdf

And another paper with the same point: extra genes make new species:

https://elifesciences.org/articles/45530

"Abstract
The Cambrian explosion was a unique animal radiation ~540 million years ago that produced the full range of body plans across bilaterians. The genetic mechanisms underlying these events are unknown, leaving a fundamental question in evolutionary biology unanswered. Using large-scale comparative genomics and advanced orthology evaluation techniques, we identified 157 bilaterian-specific genes. They include the entire Nodal pathway, a key regulator of mesoderm development and left-right axis specification; components for nervous system development, including a suite of G-protein-coupled receptors that control physiology and behaviour, the Robo-Slit midline repulsion system, and the neurotrophin signalling system; a high number of zinc finger transcription factors; and novel factors that previously escaped attention. Contradicting the current view, our study reveals that genes with bilaterian origin are robustly associated with key features in extant bilaterians, suggesting a causal relationship."

Comment: this is opposite to Behe and everything new requires genes removed, but remember we discovered Behe found this is was true only for species adaptation.