The aquaculture of yellowtail kingfish (Seriola lalandi) has expanded around the globe, including China. Genetic resource of Chinese S. lalandi urgently needs to be assessed for improving production. Here, we collected wild S. lalandi samples from the Bohai Sea, China and evaluated its genetic diversity based on 17,690 nuclear loci. A population from the Southern Ocean, Australia was used for comparison. The analyses showed that the Chinese and Australian S. lalandi formed two completely distinct clusters and there was no genetic introgression from the Australian S. lalandi into the Chinese S. lalandi population. The genetic diversity is slightly lower, but comparable in Chinese versus Australian yellowtail kingfish (Chinese population, expected heterozygosity: 0.19, observed heterozygosity: 0.19, nucleotide diversity: 0.19 ± 0.09; Australian population, expected heterozygosity: 0.23, observed heterozygosity: 0.22, nucleotide diversity: 0.22 ± 0.11). Overall, our results indicated that Chinese S. lalandi could be a potential subject for genetic breeding programs. We also investigated morphological characters and developed molecular markers for population identification. Comparison of meristic characters between the Chinese population and the Australian population revealed that main shape difference were in the number of dorsal spines, dorsal fin rays and the number of upper gill rakers. Geometric morphology based on eight landmarks also revealed significant difference between the two populations including the distance between the tip of snout to origin of pelvic fin and the distance between the tip of snout to origin of pectoral fin. These morphological characters can be used for easy identification of the Chinese S. lalandi.

Phylogenomic approaches now generate hundreds of loci representative of the whole genome that can be used for phylogenetic analyses. The South American lizard genus Liolaemus is the most species-rich vertebrate radiation from temperate zones (more than 265 described species), yet most higher-level phylogenetic relationships within Liolaemus remain poorly resolved. In this study, we used 584 nuclear loci collected using targeted sequenced capture to estimate the phylogenetic relationships among 26 species representing the two subgenera within Liolaemus (Eulaemus + Liolaemus), and all major groups within Eulaemus. Previous molecular and morphological-based phylogenetic analyses of Eulaemus based on a limited number of characters resolved few higher-level relationships, although one point of agreement is that the early divergence within Eulaemus corresponds to the lineomaculatus section, followed by the diversification of eight main clades that are strongly supported and recognized. Liolaemus probably experienced relatively rapid divergences during parts of its evolutionary history, and a phylogenomic approach was used to resolve the relationships among the major groups. The new analyses presented here support the division of Liolaemus into two subgenera, and resolve relationships among many of the major clades of Eulaemus with strong support. A Bayesian divergence dating analysis using 44 protein-coding genes provides an estimation of the split of the two Liolaemus subgenera of approximately 19,7 ma (95% HPD = 16,94 – 23,04), while diversification within Eulaemus started at 15,05 ma (95% HPD = 12,94 – 17,59) among the L. lineomaculatus and the L. montanus series by Mid Miocene. A novel phylogenetic network analyses for SNP data identified two hybridizing edges among different groups of Eulaemus at different points in time. Having a solid phylogenetic hypothesis of the main Eulaemus clades opens new opportunities to test a variety of macroevolutionary questions for this unique radiation.

Abstract Drosophila males have evolved a unique system of chromosome segregation in meiosis that lacks recombination. Chromosomes pair at selected sequences suggesting that early steps of meiosis may also differ in this organism… Diploid germline cells must undergo two consecutive meiotic divisions before differentiating as haploid sex cells. During meiosis I, homologs pair and remain conjoined until segregation at anaphase. Drosophila melanogaster spermatocytes are unique in that the canonical events of meiosis I including synaptonemal complex formation, double-strand DNA breaks, and chiasmata are absent. Sex chromosomes pair at intergenic spacer sequences within the ribosomal DNA (rDNA). Autosomes pair at numerous euchromatic homologies, but not at heterochromatin, suggesting that pairing may be limited to specific sequences. However, previous work generated from genetic segregation assays or observations of late prophase I/prometaphase I chromosome associations fail to differentiate pairing from maintenance of pairing (conjunction). Here, we separately examined the capability of X euchromatin to pair and conjoin using an rDNA-deficient X and a series of Dp(1;Y) chromosomes. Genetic assays showed that duplicated X euchromatin can substitute for endogenous rDNA pairing sites. Segregation was not proportional to homology length, and pairing could be mapped to nonoverlapping sequences within a single Dp(1;Y). Using fluorescence in situ hybridization to early prophase I spermatocytes, we showed that pairing occurred with high fidelity at all homologies tested. Pairing was unaffected by the presence of X rDNA, nor could it be explained by rDNA magnification. By comparing genetic and cytological data, we determined that centromere proximal pairings were best at segregation. Segregation was dependent on the conjunction protein Stromalin in Meiosis, while the autosomal-specific Teflon was dispensable. Overall, our results suggest that pairing may occur at all homologies, but there may be sequence or positional requirements for conjunction.

Evidence of intentional dental modification practices has been found throughout Mesoamerica dating from the Early Preclassic period to the conquest. The recovery of 102 modified teeth from Midnight Terror Cave (MTC) provides a sufficiently large sample to critically examine current explanations of intentional dental modification. Paleogenomic analysis was employed in order to test hypotheses which link intentional dental modification to sex and kinship. DNA was extracted and genomic sequencing libraries were made for 27 teeth. Results show the presence of both sexes, indicating that the practice is not sex linked. The mitochondrial genome data detects a possible link between intentional dental modification and style.

HyunJung Kim, Ralph Vin B. Imatong, Thomas H. Tai. Plant Breed. Biotech. 2020;8:19-27. https://doi.org/10.9787/PBB.2020.8.1.19

Abstract. Marker selection has emerged as an important component of phylogenomic study design due to rising concerns of the effects of gene tree estimation err

Narrow-mouthed frogs (Anura: Microhylidae) are globally distributed and molecular data suggest the rapid evolution of multiple subfamilies shortly after their origin. Despite recent progress, several subfamilial relationships remain unexplored using phylogenomic data. We analysed 1,796 nuclear ultraconserved elements, a total matrix of 400,664 nucleotides, from representatives of most microhylid subfamilies. Summary method species-tree and maximum likelihood analyses unambiguously supported Hoplophryninae, as the earliest diverging microhylid and confirm Chaperininae as a junior synonym of Microhylinae. Given the emerging consensus that subfamilies from mainland Africa diverged early, microhylids have likely occupied the continent for more than 66 million years.