Reconstruction of Ancestral Genomes as a Key to Understanding the Early Evolution of Vertebrate Genotype

Abstract

The hypothesis about whole-genome duplications as the most important driver of transformation of the structure plan and lifestyle of vertebrates at the early stages of their evolution is generally accepted today. At the same time, details such as the timing and mechanisms of these duplications still remain controversial. Research into issues of periodization, number, and in which evolutionary lineages rounds of whole-genome and/or local duplications occurred in vertebrates continues as methodology and technical capabilities develop. The role of high-throughput genomic sequencing and big data analysis is increasing, which makes it possible to identify and track the history of not only individual genes or their families but of large sections of the genome, including at the chromosomal level. New opportunities allow for considering the problem at the macro level and conduct a comparative analysis of the genomic characteristics of representatives of different evolutionary groups. In this article, which is a logical continuation of an earlier review article (in 2020), the authors make an attempt to review and summarize the data of recent years, largely related to the sequencing of genomes of representatives of evolutionarily ancient (basal) groups of vertebrates and to understand the contribution of this new information to our ideas about the early evolutionary history of the vertebrate genotype. According to new data, the divergence and observed significant differences in the morphological plans of the two evolutionary lineages of vertebrates could be ensured by different scenarios of polyploidization of their genomes.