Long interspersed nuclear element-1s (LINE-1s, or L1s) are an active family of retrotransposable elements that continue to mutate mammalian genomes. Despite the large contribution of L1 to mammalian genome evolution, we do not know where active L1 particles (particles in the process of retrotransposition) are located in the cell, or how they move towards the nucleus, the site of L1 reverse transcription. Using a yeast model of LINE retrotransposition, we identified ESCRT (endosomal sorting complex required for transport) as a critical complex for LINE retrotransposition, and verified that this interaction is conserved for human L1. ESCRT interacts with L1 via a late domain motif, and this interaction facilitates L1 replication. Loss of the L1/ESCRT interaction does not impair RNP formation or enzymatic activity, but leads to loss of retrotransposition and reduced L1 endonuclease activity in the nucleus. This study highlights the importance of the ESCRT complex in the L1 life cycle and suggests an unusual mode for L1 RNP trafficking. Long interspersed nuclear elements (LINEs) are a class of retrotransposable elements that mutate mammalian genomes. LINEs have been highly successful in the human genome, multiplying to over 800,000 copies. The LINE-encoded replication machinery is also used by other retrotransposons, and in total, has been responsible for the generation of over 1/3 of human DNA sequence. To replicate, a LINE mRNA forms a ribonucleoprotein particle (RNP) with its proteins. This RNP eventually enters the nucleus to integrate a cDNA copy of itself into chromosomes. The events between RNP formation and successful integration are difficult to study and largely unknown. Here we show that the ESCRT complex plays a conserved role in LINE retrotransposition in both yeast and humans. ESCRT is a membrane budding complex involved in cellular trafficking and membrane budding/fusion. Our results imply that membranes play an integral part of LINE replication, and ESCRT may be required for RNP trafficking towards the nucleus.

The extant reptiles are one of the most diverse clades among terrestrial vertebrates and one of a few groups with instances of parthenogenesis. Due to the hybrid origin of parthenogenetic species, reference genomes of the parental species as well as of the parthenogenetic progeny are indispensable to explore the genetic foundations of parthenogenetic reproduction. Here, we report on the first genome assembly of rock lizard Darevskia valentini, a paternal species for several parthenogenetic lineages. The novel genome was used in the reconstruction of the comprehensive phylogeny of Squamata inferred independently from 7369 trees of single-copy orthologs and a supermatrix of 378 conserved proteins. We also investigated Hox clusters, the loci that are often regarded as playing an important role in the speciation of animal groups with drastically diverse morphology. We demonstrated that Hox clusters of D. valentini are invaded with transposons and contain the HoxC1 gene that has been considered to be lost in the amniote ancestor. This study provides confirmation for previous works and releases new genomic data that will contribute to future discoveries on the mechanisms of parthenogenesis as well as support comparative studies among reptiles.

Experimental data on the molecular structure and variability of microsatellite loci in unisexual and bisexual lizard species of the genus Darevskia were analyzed. The allelic variants of Du281 and ...

The study of Caucasian rock lizards of the Darevskia raddei complex represented by several subspecies is of great interest and scientific significance in connection with their participation in interspecific hybridizations with the formation of five of the seven known unisexual (parthenogenetic) species of the Darevskia genus. Here, we present genetic parameters for populations (subspecies) of D. r. raddei and D. r. nairensis based on the analysis of the variability of ten microsatellite loci of 230 individuals from 17 populations of Armenia and Nagorno-Karabakh. According to these parameters, D. r. raddei are characterized by greater diversity in the number of alleles and genotypes compared to D. r. nairensis. Genetic differentiation analysis showed that D. r. raddei populations are divided into two groups, one of which is genetically closer to D. r. nairensis than to D. r. raddei. Analysis of the association index showed the absence of free recombination of alleles between subspecies, which indicates their isolation and the absence of crossing between individuals. Thus, on the basis of the expanded population sample and the developed panel of microsatellite markers, new data on the population structure of D. raddei species and on the genetic diversity and differentiation of D. r. raddei and D. r. nairensis were obtained.

The identification of the parthenogenetic Uzzell’s lizard, Darevskia uzzelli (Darevsky & Danielyan, 1977), in Armenia represents the first record of this species in the country. Before this discovery, D. uzzelli was considered an endangered species endemic to a small region of northeastern Türkiye. Genetic and morphological analyses have confirmed that the Armenian lizards are indeed D. uzzelli, consistent with specimens from Türkiye. Morphological and genetic data also firmly discriminate D. uzzelli from the closely related parthenogenetic species D. unisexualis. Our results reveal significant morphological variation in this parthenogen among populations. Notably, the sympatric area in Armenia where D. uzzelli has been identified is unique for hosting the richest known assemblage of parthenogenetic lizards. Here, D. uzzelli coexists with three other parthenogenetic species already known to inhabit the region: D. unisexualis, D. armeniaca, and D. dahli. This exceptional population requires continuous study and protection due to its high scientific value.