Improved mammalian family phylogeny using gap-rare multiple sequence alignment:A timetree of extant placentals and marsupials

The timing of mammalian diversification in relation to the Cretaceous-Paleogene(KPg)mass extinction continues to be a subject of substantial debate.Previous studies have either focused on limited taxonomic samples with available whole-genome data or relied on short sequence alignments coupled with extensive species samples.In the present study,we improved an existing dataset from the landmark study of Meredith et al.(2011)by filling in missing fragments and further generated another dataset containing 120 taxa and 98 exonic markers.Using these two datasets,we then constructed phylogenies for extant mammalian families,providing improved resolution of many conflicting relationships.Moreover,the timetrees generated,which were calibrated using appropriate molecular clock models and multiple fossil records,indicated that the interordinal diversification of placental mammals initiated before the Late Cretaceous period.Additionally,intraordinal diversification of both extant placental and marsupial lineages accelerated after the KPg boundary,supporting the hypothesis that the availability of numerous vacant ecological niches subsequent to the mass extinction event facilitated rapid diversification.Thus,our results support a scenario of placental radiation characterized by both basal cladogenesis and active interordinal divergences spanning from the Late Cretaceous into the Paleogene.

Population genomics reveals that natural variation in PRDM16 contributes to cold tolerance in domestic cattle

Environmental temperature serves as a major driver of adaptive changes in wild organisms.To discover the mechanisms underpinning cold tolerance in domestic animals,we sequenced the genomes of 28 cattle from warm and cold areas across China.By characterizing the population structure and demographic history,we identified two genetic clusters,i.e.,northern and southern groups,as well as a common historic population peak at 30 kilo years ago.Genomic scan of cold-tolerant breeds determined potential candidate genes in the thermogenesis-related pathways that were under selection.Specifically,functional analysis identified a substitution of PRDM16(p.P779 L)in northern cattle,which maintains brown adipocyte formation by boosting thermogenesis-related gene expression,indicating a vital role of this gene in cold tolerance.These findings provide a basis for genetic variation in domestic cattle shaped by environmental temperature and highlight the role of reverse mutation in livestock species.

Phosphoribosyl-pyrophosphate synthetase 2 (PRPS2)depletion regulates spermatogenic cell apoptosis and is correlated with hypospermatogenesis

Phosphoribosyl-pyrophosphate synthetase 2(PRPS2)is a rate-limiting enzyme and plays an important role in purine and pyrimidine nucleotide synthesis.Recent studies report that PRPS2 is involved in male infertility.However,the role of PRPS2 in hypospermatogenesis is unknown.In this study,the relationship of PRPS2 with hypospermatogenesis and spermatogenic cell apoptosis was investigated.The results showed that PRPS2 depletion increased the number of apoptotic spermatogenic cells in vitro.PRPS2 was downregulated in a mouse model of hypospermatogenesis.When PRPS2 expression was knocked down in mouse testes,hypospermatogenesis and accelerated apoptosis of spermatogenic cells were noted.E2F transcription factor 1(E2F1)was confirmed as the target gene of PRPS2 and played a key role in cell apoptosis by regulating the P53/Bcl-xl/Bcl-2/Caspase 6/Caspase 9 apoptosis pathway.Therefore,these data indicate that PRPS2 depletion contributes to the apoptosis of spermatogenic cells and is associated with hypospermatogenesis,which may be helpful for the diagnosis of male infertility.

Copper-Mediated and Catalyzed C-H Bond Amination via Chelation Assistance: Scope, Mechanism and Synthetic Applications

Nitrogen-containing compounds are ubiquitously found in the fields of organic chemistry,pharmaceuticals,agrochemicals,medicinal chemistry and functional materials.The C-H bond amination reaction is one of the most straightforward protocols in the CN bond formation,showing"step"and"atomic"economy.As a catalyst for C-H amination reaction,copper exhibits its unique catalytic properties due to easily accessible oxidation states.The research progress of copper-catalyzed C-H amination in recent years is summarized.At the same time,reaction mechanisms are also briefly described in representative aminations to provide insights for the development prospects of highly practical and more environmentally benignprocesses.