Vol 56, No 3 (2025)

Genes of the ANTP classare known as evolutionary conserved and hierarchically high-level regulators ofdevelopment. They are the most studied and the most numeroushomeobox genes in animals. These genes encode homeodomain transcription factorsand possess a set of unique features, such as clustering,colinearity, evolutionary conservation, and consistent involvement in various differentiation processesthroughout the ontogeny of multicellular animals. The first ANTP genes (fromthe NK subclass) appear in ctenophores and sponges, which iswhy the evolution of Metazoa from a common unicellular ancestoris often associated with the emergence of the ANTP class(Larroux et al., 2007; Moroz et al., 2014). Phylogenetic analysisof homeobox genes, conducted across a broad range of basalMetazoa taxa, has shown that ANTP genes from the Hoxand ParaHox subclasses arose in the last common ancestor ofCnidaria and Bilateria. These new findings raise further questions. Howdoes the evolution of these clusters correlate with the evolutionof animals? What functions were acquired by the new genes,and which were inherited from ancestral NK genes? What changesin their regulation could have influenced the evolution of bodyplans in Metazoa? Is it even possible to answer thesequestions by studying modern multicellular organisms? This review aims to addressthese and other questions regarding the evolution of ANTP geneclusters. Special attention is given to the concept of the“megacluster”—a hypothetical synteny that united all ANTP subclassesat the dawn of Metazoa evolution. The decreasing cost of sequencingtechnologies offers some hope for answers, as it expands therange of model species available for study. The broader thisrange, the easier it becomes to identify universal and lineage-specificpatterns of molecular and morphological evolution.

In this article, I analyze the outstanding contributionof Russian-American researcher Vera Danchakoff (1879–1950) — her pioneeringwork on the blood stem cells and on the plasticityof embryonic development. I argue that, working along the samelines, as the Russian histologist Alexander Maximow, Danchakoff described theunique properties of the “polyvalent” (pluripotent) stem cells, and was,in fact, the first author who used the term “stemcell” in its modern meaning in her 1917 publication. Developingthe idea of polyvalent cell differentiation, she applied it toembryonic development in her research on the cultivation of humanembryonic tissues on the chorioallantoic membrane of chicken. I showthat these experiments, which Danchakoff conducted during her stay inSoviet Russia in 1926–1932, were formative for her later researchon the problem of sex determination and the bipotentiality ofprimordia of the gonads and sexual organs.

A characteristic feature ofCaucasian rock lizards is the diversity of parthenogenetic species andthe ongoing processes of interspecific hybridization in the zones ofsympatry of unisexual and bisexual species with the formation ofpolyploid hybrids. This is the reason for the interest instudying the species composition of various, especially mixed, populations ofDarevskia. According to the preliminary description of the morphologicalcharacteristics of lizards from the previously unstudied Jradzor population ofArmenia, it was assumed that only unisexual individuals live init, but the affiliation of the species was questioned. Inthe present work, microsatellite genotyping of lizards from this population(n = 24) was carried out using locus-specific PCR andsubsequent full-length sequencing of the identified alleles. As a result,the species composition of this sample was established, including individualsof the parthenospeciesDarevskia dahli,D. unisexualis,andD. armeniaca. Individuals identified asD. dahlihave the same alleles from the studied loci as inother populations of Armenia. However, the multilocus genotypes formed bythe alleles are different. The individual identified asD. armeniacacarries the most common multilocus genotype. In D. unisexualisindividuals,a new allele (allele B) was identified at the Du281locus, which reflects the phenomenon of intraspecific polymorphism of parthenogeneticspecies. Thus, an unusual feature of the Jradzor population isthe sympatric habitation of three and possibly four parthenogenetic speciesofDarevskia, if the presence of D. uzzellii in Armenia is further confirmed.