Developmental regulation of conserved non-coding element evolution provides insights into limb loss in squamates

Limb loss shows recurrent phenotypic evolution across squamate lineages.Here,based on three de novo-assembled genomes of limbless lizards from different lineages,we showed that divergence of conserved non-coding elements(CNEs)played an important role in limb development.These CNEs were associated with genes required for limb initiation and outgrowth,and with regulatory signals in the early stage of limb development.Importantly,we identified the extensive existence of insertions and deletions(In Dels)in the CNEs,with the numbers ranging from 111 to 756.Most of these CNEs with In Dels were lineagespecific in the limbless squamates.Nearby genes of these In Del CNEs were important to early limb formation,such as Tbx4,Fgf10,and Gli3.Based on functional experiments,we found that nucleotide mutations and In Dels both affected the regulatory function of the CNEs.Our study provides molecular evidence underlying limb loss in squamate reptiles from a developmental perspective and sheds light on the importance of regulatory element In Dels in phenotypic evolution.

Exploring the first occurrence of Scincomorpha lizard from Nenjiang Formation(lower Campanian)of Jilin,Northeast China:a follow-up study

In a region where lizard fossils are rare,this study explores a groundbreaking discovery of squamate lizard materials from the upper part of Nenjiang Formation(early Campanian)in Jilin Province,Northeast China.Despite the fragmentary nature of the dentaries,they exhibit distinct tooth morphological characteristics of squamate lizards,suggesting insectivorous and omnivorous diets for these small reptiles.This finding not only represents a significant addition to the squamate lizard fossil records from the Late Cre-taceous in Northeast China but also contributes to our understanding of the paleogeographic distribution of squamate lizards.Furthermore,it sheds new light on the terrestrial vertebrate fauna of the Cretaceous Songliao Basin.

Complete Sequence and Gene Organization of the Mitochondrial Genome of Tokay (Gekko gecko)

Long-PCR amplification, clone and primer-walking sequencing methods were employed in determine the complete sequence of mitochondrial genome of tokay (Gekko gecko). The genome is 16 435 bp in size, contains 13 protein-coding, 2 ribosomal and 22 transfer RNA genes. The mt genome of Gekko is similar to most of the vertebrates in gene components, order, orientation, tRNA structures, low percentage of guanine and high percentage of thymine, and skews of base GC and AT. Base A was preferred at third codon positions for protein genes is similar to amphibians and fishes rather than amnion vertebrates. The standard stop codes (TAA) present only in three protein genes, less than those of most vertebrates. Transfer RNA genes range in length from 63 to 76 nt, their planar structure present characteristic clover leaf, except for tRNA-Cys and tRNA-Ser (AGY) because of lacking the D arm.