Month: September 2022

LOGICAL STRATEGY. "Within a population, morphological change can occur via divergence in regulatory genes, leading to variation in gene expression, and thus the extrapolation to morphological evolution proceeding via diversification in regulatory loci provides a logical foundation for investigating the genetics underlying developmental evolution." https://lnkd.in/dD4GcAS View in LinkedIn

FIRST STEP. "Novel phenotypes arise as a result of a particular mutation or combination of mutations becoming fixed in a population, but, in order for this to occur, the genetic change must first be tolerated by the developing organism and be inherited by its offspring." https://lnkd.in/dD4GcAS View in LinkedIn

CONTROL OF MORPHOLOGICAL TRAITS. "Unlike biochemical or physiological traits, morphological traits are typically specified by genes that act upstream in major developmental pathways. As such, mutations in coding regions (‘functional’ mutations) were considered to incur sufficiently deleterious pleiotropy to be untenable for effecting morphological evolution." https://lnkd.in/dD4GcAS View in LinkedIn

MORPHOLOGICAL GENE MUTATIONS. "Mutations in regulatory regions were thus thought to be the main force for morphological evolution, as changes in gene regulation impacting timing and/or position of gene expression were likely to be better tolerated as a result of their more subtle effects in a restricted set of tissues during development." https://lnkd.in/dD4GcAS View in LinkedIn

REGULATORY MUTATIONS. "Unlike with functional mutations, regulatory mutations would not impact the physical interactions and function of the encoded protein, enabling essential metabolic or cellular functions to proceed." https://lnkd.in/dD4GcAS View in LinkedIn

SPARED BY REDUNDANCY. "Because of modularity in plant development and redundancy in GRNs underlying developmental processes, however, a change in a protein sequence may not have the massive negative pleotropic effects that were once considered to eliminate such changes from playing a role in developmental evolution." (GRN = gene regulatory networks). https://lnkd.in/dD4GcAS View in LinkedIn

NETWORK BUFFERING. "The same benefits of modularity that were evoked to hypothesize why cis-regulatory changes would be less pleiotropic than functional changes apply as well to the modularity of GRNs as effectors of gene regulation and expression, with the GRN acting as a buffer against any widespread negative effects of a coding mutation in a developmental gene." (GRN = gene regulatory networks). https://lnkd.in/dD4GcAS View in LinkedIn

SILENT DUPLICATION EFFECTS. "Mutations in the coding regions of genes involved in a regulatory network can cause changes in protein–protein interactions, but these interactions could occur in a restricted, tissue-specific manner and impact a subset of developmental functions. The presence of duplicated genes means that mutations and subsequent drift or natural selection affecting genes or their targets can occur without necessarily changing the essential function of an existing GRN." (GRN = gene regulatory networks). https://lnkd.in/dD4GcAS View in LinkedIn

SO ENDS this consideration of the genetic drivers of flower shape. This was a difficult topic but hopefully worth it. Animals and plants differ significantly in their construction and underlying genetics, and the rampant gene duplication in plants appears to give a vast range of options for natural selection to act upon and allow considerable phenotypic diversity to emerge. View in LinkedIn

KEY FACTORS OF VIRUSES. "Most pathogens have large population sizes and short generation times. This is particularly true for viruses. The complete replication-cycle of a virus within a host cell often takes only a few hours and results in many thousands new viruses. Because the viral RNA-polymerase does not possess a proof-reading-function, faulty nucleotides are integrated during replication with a likelihood of 10(-3) to 10(-4), which results in high mutation rates. In fact, the error rate of the viral RNA-polymerase is 1000 times higher than the error rate of the human DNA- polymerase." https://lnkd.in/d8xM5QF View in LinkedIn