A brief review on the strategy for selection of orthology prediction methods in phylogenomic studies

With the development and decreasing cost of sequencing techniques, it is possible for scientists to conduct deeper research in phylogenomics. During the procedure of phylogenomic analysis, the mostimportant and vitalest step is orthology prediction, for that the prerequisite to phylogenetic reconstruction is that the genes being compared are orthologous. Here we briefly review the related concept of orthology anddifferent methods for orthology prediction. We also provide recommendations to give some advice for better selection of orthology prediction methods.

LZ Complexity Distance of DNA Sequences and Its Application in Phylogenetic Tree Reconstruction

DNA sequences can be treated as finite-length symbol strings over a four-letter alphabet （A, C, T, G）. As a universal and computable complexity measure, LZ complexity is valid to describe the complexity of DNA sequences. In this study, a concept of conditional LZ complexity between two sequences is proposed according to the principle of LZ complexity measure. An LZ complexity distance metric between two nonnull sequences is defined by utilizing conditional LZ complexity. Based on LZ complexity distance, a phylogenetic tree of 26 species of placental mammals （Eutheria） with three outgroup species was reconstructed from their complete mitochondrial genomes. On the debate that which two of the three main groups of placental mammals, namely Primates, Ferungulates, and Rodents, are more closely related, the phylogenetic tree reconstructed based on LZ complexity distance supports the suggestion that Primates and Ferungulates are more closely related.

Root Endophyte Shift and Key Genera Discovery in Rice under Barnyardgrass Stress

Despite increasing knowledge of barnyardgrass(Echinochloa crus-galli) interference with rice, relatively little is known how endophytes improve the ability of rice against barnyardgrass stress. Here, we provided a detailed temporal characterization of rice root-associated microbiomes during co-cultivation with barnyardgrass and a comparison with the microbiomes of weed-free rice plants. Alpha diversity analysis indicated that barnyardgrass had the opposite effects on endophytic bacteria and fungi in rice roots, in terms of the community diversity, richness and coverage at the rice seedling stage. Principal coordinate analysis showed that barnyardgrass had only a minor effect on the community composition of endophytes in rice roots at the rice seedling stage, but showed a significant and maximum interference at the heading stage. Rice recruited many endophytes to resist biotic stress from barnyardgrass, especially for fungi. PICRUSt(phylogenetic investigation of communities by reconstruction of unobserved states) predictive analysis indicated that 23 metabolic pathways of bacteria were overrepresented in rice. In addition, the main trophic mode of fungi was pathotroph according to FUNGuild analysis. A positive correlation between bacteria and fungi in rice roots was found via network analysis. Anaeromyxobacter, Azospira and Pseudolabrys were the vital bacteria, Phaeosphaeria and Funneliformis were the dominant fungi in maintaining the stability of the ecological network. These results provided data and a theoretical basis for the in-depth understanding of what role endophytes play in rice resistance to barnyardgrass stress and will have implications on improving the resistance of rice against biotic stress using root microbiota.

Phylogenetic relationships of five genera of Xylariales and Rosasphaeria gen.nov.(Hypocreales)

Eight inconspicuous non-stromatic perithecial fungi immersed in plant tissue are assessed with respect to their morphology,ecology and phylogenetic position.Emphasis is laid on two genera now and then placed in the family Hyponectriaceae,Xylariales:Leiosphaerella with its type species L.praeclara occurring on Vaccinium,and Pseudomassaria with its type species P.chondrospora occurring on Tilia.In molecular phylogenetic analyses of LSU and ITS sequences,the generic types of these genera are closely related,but their familial affiliation within Xylariales remains unresolved.Pseudomassaria sepincoliformis clusters with P.chondrospora,whereas P.fallax is not congeneric with Pseudomassaria and P.lycopodina is combined in Leiosphaerella despite its apiospores.Three species thought to belong to Leiosphaerella are re-assessed:L.moravica that occurs on Rosa,is disposed in the new genus Rosasphaeria,which is close to Eucasphaeria in the Niessliaceae(Hypocreales),according to multi-gene phylogenetic analyses(ITS,LSU,rpb2 and tef1).For L.vexata the genus Pseudomassariella is revived.A Leiosphaerellalike fungus on Lycopodium is described as the new species Monographella lycopodina.In addition the phylogenetic relationships of two fungi forming superficial stromata are here clarified:Collodiscula japonica belongs to the Xylariaceae,while Melogramma campylosporum may currently be interpreted as representing a family of its own,the Melogrammataceae.

Comprehensive analyses for genetic diversities of 19 autosomal STRs in Chinese Kazak group and its phylogenetic relationships with other continental populations

Short tandem repeats(STRs)play an essential role in forensic genetics due to their high degree of polymorphisms,wide distributions and easy detection method.In this study,allelic frequencies and forensic statistical parameters of the 19 autosomal STR loci in a Kazak ethnic group were calculated,and its genetic relationships with reference populations were assessed in order to understand population structure better and enrich population genetic data for forensic practice in Chinese Kazak ethnic group.There were 226 identified alleles with the corresponding allelic frequencies ranging from 0.0008 to 0.5295 in the 628 unrelated healthy Kazak individuals in Xinjiang Uygur Autonomous Region.All autosomal STRs were conformed to the Hardy-Weinberg equilibrium after Bonferroni’s correction.The cumulative power of discrimination and the combined probability of exclusion of all the 19 autosomal STRs were 0.999999999999999999999997162 and 0.999999994484,respectively.Furthermore,the DA distances and Fixation index values of pairwise populations,principal component analysis,multidimensional scaling analysis,phylogenetic tree analysis and structure analysis were conducted to probe the genetic relationships between the Kazak group and other reference populations.The population genetic results showed that these 19 autosomal STR loci were characterised by high genetic diversities in the Kazak group.Furthermore,the studied Kazak group had close genetic relationships with the Uyghur group and the Uzbek group.The present results may facilitate understanding the genetic background of the Chinese Xinjiang Kazak group.

Genetic and structural characterization of 20 autosomal short tandem repeats in the Chinese Qinghai Han population and its genetic relationships and interpopulation differentiations with other reference populations

China is a multinational country composed of 56 ethnic groups of which the Han Chinese accounts for 91.60%.Qinghai Province is located in the northeastern part of the Qinghai-Tibet Plateau,has an area of 72.12 km2,and is the fourth largest province in China.In the present study,we investigated the genetic polymorphisms of 20 short tandem repeat (STR) loci in a Qinghai Han population,as well as its genetic relationships with other populations.A total of 273 alleles were identified in 2 000 individuals at 20 loci,and the allelic frequency ranged from 0.0002 to 0.5327.The 20 STR loci showed a relatively high polymorphic rate in the studied group.Observed and expected heterozygosities ranged 0.613 0-0.907 5 and 0.614 8-0.920 0,respectively.The combined power of discrimination,and the probability of exclusion in duo and trio cases were 0.999 999 999 999 999 999 999 999 34,0.9999960 and 0.9999999965,respectively.Analyses of interpopulation differentiation revealed that the most significant differences were found between the Qinghai Han and Malaysian,while no significant differences were found between the Qinghai Han and Han people from Shaanxi and Jiangsu.The results of principal component analysis,multidimensional scaling analysis and phylogenetic reconstructions also suggested the close relationships between the Qinghai Han and other two Han populations.The present results,therefore,indicated that these 20 STR loci could be used for paternity testing and individual identification in forensic applications,and may also provide information for the studies of genetic relationships between Qinghai Han and other groups.