The Yangtze River is cross-linked with numerous lakes within its floodplain and is a worldwide biodiversity hotspot. There is no evidence indicating when this unique river-lake system developed. The endemic East Asian cyprinid clade has evolved diverse spawning adaptations to different flow conditions. Our ancestral egg-type reconstruction showed an ancestral state of adhesive eggs and later demersal eggs origination (both stream adaptations). Semi-buoyant eggs emerged ~18 Mya as a fast-flowing river adaptation, with increased hydration via three yolk protein degradation pathways, ion transport pathways and egg envelope permeability transition pores. Adhesive eggs evolved secondarily ~14 Mya with the egg envelope increasing to four layers and an adhesive layer, along with an increase in adhesiveness via microfilament/adhesive-related protein crosslinking and enhanced glycosaminoglycan biosynthesis, improving adherence to submerged lake plants, indicating that the cross-linked river-lake system formed in the mid-Miocene. This study provides a unique biological evidence for large-scale water system evolution.

The coronavirus disease 2019 (COVID-19) was officially declared a pandemic on the 11^th March 2020. It is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), impacting the lower respiratory tract. International travel to Australia during the early stages of the pandemic prior to border closure provided avenues for this virus to spread into Australia. There is little understanding of the clonality of SARS-CoV-2 isolates in Australia, and where they originated. This study aimed to investigate the clonality and ancestral sources of SARS-CoV-2 isolates in Australia using in silico methods. We retrieved 1,346 complete genomes from Australia along with 153 genomes from other countries from the NCBI nucleotide database and Global Initiative On Sharing All Influenza Data (GISAID). We then constructed a representative population of 270 sequences for downstream phylogenetic analysis and ancestral area reconstruction. Overall, two major clusters, one stemming from Europe and another from Asia, especially East Asia, were observed, implying at least two major transmission events with subsequent clades confirming the multiclonality of Australian isolates. We also identified three potential dissemination routes of SARS-CoV-2 into Australia. This study supports the hypothesis of multiple clonality and dispersals of SARS-CoV-2 isolates into Australia.

Considering that life on earth evolved about 3.7 billion years ago, vertebrates are young, appearing in the fossil record during the Cambrian explosion about 542 to 515 million years ago. Results from sequence analyses of genomes from bacteria, yeast, plants, invertebrates and vertebrates indicate that receptors for adrenal steroids (aldosterone, cortisol), and sex steroids (estrogen, progesterone, testosterone) also are young, with an estrogen receptor and a 3-ketosteroid receptor first appearing in basal chordates (cephalochordates: amphioxus), which are close ancestors of vertebrates. Through gene duplication and divergence of the 3-ketosteroid receptor, receptors that respond to androgens, glucocorticoids, mineralocorticoids and progestins evolved in vertebrates. Thus, an ancestral progesterone receptor and an ancestral corticoid receptor, the common ancestor of the glucocorticoid and mineralocorticoid receptors, evolved in jawless vertebrates (cyclostomes: lampreys, hagfish). This was followed by evolution of an androgen receptor, distinct glucocorticoid and mineralocorticoid receptors and estrogen receptor-α and -β in cartilaginous fishes (gnathostomes: sharks). Further evolution of mineralocorticoid signaling occurred with the evolution of aldosterone synthase in lungfish, a forerunner of terrestrial vertebrates. Adrenal and sex steroid receptors are not found in echinoderms: and hemichordates, which are ancestors in the lineage of cephalochordates and vertebrates. The evolution of steroid receptors at key nodes in the evolution of vertebrates, in which steroid receptors act as master switches to regulate differentiation, development, reproduction, immune responses, electrolyte homeostasis and stress responses, argues for an important role for steroid receptors in the evolutionary success of vertebrates, considering that the human genome contains about 22,000 genes, which is not much larger than genomes of invertebrates, such as Caenorhabditis elegans (~18,000 genes) and Drosophila (~14,000 genes).

Most Neotropical Psittacidae have a diploid number of 2n=70, and a dichotomy in chromosome patterns. Long-tailed species have biarmed macrochromosomes, while short - tailed ones have telo/acrocentric macrochromosomes. However, the use of chromosome painting with chicken and white hawk probes has demonstrated that karyotype evolution in Psittacidae includes a high number of inter/intrachromosomal rearrangements. Hence, to determine the phylogeny of Long and Short-Tailed species, and to propose a putative ancestral karyotype for this group, we constructed homology maps of Pyrrhura frontalis (PFR) and Amazona aestiva (AAE) and compared them to other previously analyzed long-tailed species. Chromosomes were analyzed by conventional staining and fluorescent in situ hybridization (FISH) using whole chromosome paints of G. gallus (GGA) and L. albicollis (LAL). Conventional staining showed a karyotype with 2n=70 in both species, with biarmed macrochromosomes in Pyrrhura frontalis and telo/acrocentric chromosomes in Amazona aestiva. Comparison of the results with the putative avian ancestral karyotype (PAK) showed fusions in P. frontalis of PAK1p/PAK4q (PFR1) and PAK6/PAK7 (PFR6) with a paracentric inversion in PFR6. However, in A. aestiva there was only the fusion between PAK6/7 (AAE7) with a paracentric inversion. Hybridizations with LAL probes confirmed these results. The results indicate that PFR retained a more basal karyotype than Anodorhynchus hyacinthinus (AHY), Ara macao (AMA) and Ara chloropterus (ACH), because these three species show the fusion PAK8/PAK9 that is not seen in PFR. Hence, we suggest that the ancestral karyotype of species with biarmed chromosomes have the fusions PAK1p/PAK4 and PAK6/PAK7 and, additionally, a pericentric inversion of PAK6/PAK7, while the fusion PAK8/PAK9 would have appeared in the common ancestor of Anodorhynchus hyacinthinus, Ara macao and Ara chloropterus. However, the species A. aestiva shows a characteristic plesiomorphic trait, since PAK1p/PAK4q and PAK8/9 fusions are absent. Our results base on chromosome rearrangements suggest the classification following the criterium of tail length may no reflect the real phylogenetic history of Neotropical Psittacidae.

Authors evaluated the relevant literature related to the purging which is the interaction between selection and inbreeding where the population may get rid of its inbreeding load at least partially. The backroad of the relevant theory was given and the available methods were described both based on the conventional quantitative genetic approach (based on genealogy data) and based on the latest genomic methods. The different parameters necessary for signalling purging (highlighting those inbreeding coefficients which are not yet been widely known in animal and veterinary science) were presented together with the relevant results of the literature. The available statistical methods together with the softwares and R packages to calculate various inbreeding coefficients and to determine inbreeding depression and purging were provided. The main results of the different approaches obtained in laboratory ZOO and domesticated populations (lethal equivalents, ancestral inbreeding, Inbreeding-Purging Model, genomic approaches) were summarized and presented. Application possibilities and future prospective of purging was also discussed.