AUTHOR=Ermakova Galina V. , Kucheryavyy Alexander V. , Mugue Nikolay S. , Mischenko Aleksandr V. , Zaraisky Andrey G. , Bayramov Andrey V. 

TITLE=Three foxg1 paralogues in lampreys and gnathostomes—brothers or cousins?

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2023.1321317

DOI=10.3389/fcell.2023.1321317

ISSN=2296-634X

ABSTRACT=<p><italic>Foxg1</italic> is a key regulator of the early development of the vertebrate forebrain and sensory organs. In this study, we describe for the first time three <italic>foxg1</italic> paralogues in lamprey, representative of one of two basally diverged lineages of vertebrates—the agnathans. We also first describe three <italic>foxg1</italic> genes in sterlet—representative of one of the evolutionarily ancient clades of gnathostomes. According to the analysis of local genomic synteny, three <italic>foxg1</italic> genes of agnathans and gnathostomes have a common origin as a result of two rounds of genomic duplications in the early evolution of vertebrates. At the same time, it is difficult to reliably establish pairwise orthology between <italic>foxg1</italic> genes of agnathans and gnathostomes based on the analysis of phylogeny and local genomic synteny, as well as our studies of the spatiotemporal expression of <italic>foxg1</italic> genes in the river lamprey <italic>Lampetra fluviatilis</italic> and the sterlet <italic>Acipenser ruthenus</italic>. Thus, the appearance of three <italic>foxg1</italic> paralogues in agnathans and gnathostomes could have occurred either as a result of two rounds of duplication of the vertebrate common ancestor genome (2R hypothesis) or as a result of the first common round followed by subsequent independent polyploidizations in two evolutionary lineages (1R hypothesis).</p>