No abstract

Proteins of the Split ends (Spen) family are characterized by an N-terminal domain, with one or more RNA recognition motifs and a SPOC domain. In Arabidopsis thaliana, the Spen protein FPA is involved in the control of flowering time as a component of an autonomous pathway independent of photoperiod. The A. thaliana genome encodes another gene for a putative Spen protein at the locus At4g12640, herein named AtSpen2. Bioinformatics analysis of the AtSPEN2 SPOC domain revealed low sequence similarity with the FPA SPOC domain, which was markedly lower than that found in other Spen proteins from unrelated plant species. To provide experimental information about the function of AtSpen2, A. thaliana plants were transformed with gene constructs of its promoter region with uidA::gfp reporter genes; the expression was observed in vascular tissues of leaves and roots, as well as in ovules and developing embryos. There was absence of a notable phenotype in knockout and overexpressing lines, suggesting that its function in plants might be specific to certain endogenous or environmental conditions. Our results suggest that the function of Atspen2 diverged from that of fpa due in part to their different transcription expression pattern and divergence of the regulatory SPOC domain.

No abstract

Identification of species boundaries within the genus Aspidoscelis is one of the most complex tasks in herpetological systematics due to the extensive morphological variation and complex evolutionary history involved. The whiptail lizard Aspidoscelis lineattissimus is a polymorphic species that inhabits tropical ecosystems over a wide region of western Mexico and is currently classified into four subspecies, A. l. exoristus, A. l. lineattissimus, A. l. lividus and A. l. duodecemlineatus. In this study, we used phylogenetic and coalescent‐based approaches to disentangle the phylogenetic relationships among the subspecies of A. lineattissimus and to assess the level of differentiation between these subspecific taxa. We also inferred the divergence times and historical biogeography to reconstruct the evolutionary history of the A. lineattissimus complex. Three mitochondrial genes (ND4, 12S and 16S) and one nuclear exon (BACH1) were used, along with comprehensive sampling that included individuals representing the four subspecies. Coalescence analyses supported three well‐differentiated lineages as independent evolutionary units, corresponding to A. l. exoristus, A. l. lineattissimus + A. l. lividus and A. l. duodecemlineatus, partially recovering the previous classification. Furthermore, phylogenetic analyses support three additional discrete lineages within A. l. duodecemlineatus. Finally, divergence time estimates and reconstructions of ancestral areas indicated that the origin and diversification of the five differentiated lineages within the A. lineattissimus complex was strongly associated with oscillations in sea level due to glacial/interglacial climatic fluctuations beginning in the Mid‐Pliocene. Our research highlights the importance of phylogenetic studies within the genus Aspidoscelis to disentangle their evolutionary history and reveal hitherto underestimated diversity.