independent evolution
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Animals ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 148
Author(s):  
Watcharaporn Thapana ◽  
Nattakan Ariyaraphong ◽  
Parinya Wongtienchai ◽  
Nararat Laopichienpong ◽  
Worapong Singchat ◽  
...  

Duplicate control regions (CRs) have been observed in the mitochondrial genomes (mitogenomes) of most varanids. Duplicate CRs have evolved in either concerted or independent evolution in vertebrates, but whether an evolutionary pattern exists in varanids remains unknown. Therefore, we conducted this study to analyze the evolutionary patterns and phylogenetic utilities of duplicate CRs in 72 individuals of Varanus salvator macromaculatus and other varanids. Sequence analyses and phylogenetic relationships revealed that divergence between orthologous copies from different individuals was lower than in paralogous copies from the same individual, suggesting an independent evolution of the two CRs. Distinct trees and recombination testing derived from CR1 and CR2 suggested that recombination events occurred between CRs during the evolutionary process. A comparison of substitution saturation showed the potential of CR2 as a phylogenetic marker. By contrast, duplicate CRs of the four examined varanids had similar sequences within species, suggesting typical characteristics of concerted evolution. The results provide a better understanding of the molecular evolutionary processes related to the mitogenomes of the varanid lineage.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jalen Singh ◽  
Pranav Pandit ◽  
Andrew G. McArthur ◽  
Arinjay Banerjee ◽  
Karen Mossman

AbstractThe emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and more recently, the independent evolution of multiple SARS-CoV-2 variants has generated renewed interest in virus evolution and cross-species transmission. While all known human coronaviruses (HCoVs) are speculated to have originated in animals, very little is known about their evolutionary history and factors that enable some CoVs to co-exist with humans as low pathogenic and endemic infections (HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1), while others, such as SARS-CoV, MERS-CoV and SARS-CoV-2 have evolved to cause severe disease. In this review, we highlight the origins of all known HCoVs and map positively selected for mutations within HCoV proteins to discuss the evolutionary trajectory of SARS-CoV-2. Furthermore, we discuss emerging mutations within SARS-CoV-2 and variants of concern (VOC), along with highlighting the demonstrated or speculated impact of these mutations on virus transmission, pathogenicity, and neutralization by natural or vaccine-mediated immunity.


2021 ◽  
Author(s):  
Jan Engelhardt ◽  
Oliver Scheer ◽  
Peter F Stadler ◽  
Sonja J. Prohaska

DNA methylation is a crucial, abundant mechanism of gene regulation in vertebrates. It is less prevalent in many other metazoan organisms and completely absent in some key model species, such as D. melanogaster and C. elegans. We report here a comprehensive study of the presence and absence of DNA methyltransferases (DNMTs) in 138 Ecdysozoa, covering Arthropoda, Nematoda, Priapulida, Onychophora, and Tardigrada. Three of these phyla have not been investigated for the presence of DNA methylation before. We observe that the loss of individual DNMTs independently occurred multiple times across ecdysozoan phyla. We computationally predict the presence of DNA methylation based on CpG rates in coding sequences using an implementation of Gaussian Mixture Modelling, MethMod. Integrating both analysis we predict two previously unknown losses of DNA methylation in Ecdysozoa, one within Chelicerata (Mesostigmata) and one in Tardigrada. In the early-branching Ecdysozoa Priapulus caudatus we predict the presence of a full set of DNMTs and the presence of DNA methylation. We are therefore showing a very diverse and independent evolution of DNA methylation in different ecdysozoan phyla spanning a phylogenetic range of more than 700 million years.


2021 ◽  
Vol 12 ◽  
Author(s):  
Katherine Chacón-Vargas ◽  
Colin O. McCarthy ◽  
Dasol Choi ◽  
Long Wang ◽  
Jae-Hyuk Yu ◽  
...  

Microbes (bacteria, yeasts, molds), in addition to plants and animals, were domesticated for their roles in food preservation, nutrition and flavor. Aspergillus oryzae is a domesticated filamentous fungal species traditionally used during fermentation of Asian foods and beverage, such as sake, soy sauce, and miso. To date, little is known about the extent of genome and phenotypic variation of A. oryzae isolates from different clades. Here, we used long-read Oxford Nanopore and short-read Illumina sequencing to produce a highly accurate and contiguous genome assemble of A. oryzae 14160, an industrial strain from China. To understand the relationship of this isolate, we performed phylogenetic analysis with 90 A. oryzae isolates and 1 isolate of the A. oryzae progenitor, Aspergillus flavus. This analysis showed that A. oryzae 14160 is a member of clade A, in comparison to the RIB 40 type strain, which is a member of clade F. To explore genome variation between isolates from distinct A. oryzae clades, we compared the A. oryzae 14160 genome with the complete RIB 40 genome. Our results provide evidence of independent evolution of the alpha-amylase gene duplication, which is one of the major adaptive mutations resulting from domestication. Synteny analysis revealed that both genomes have three copies of the alpha-amylase gene, but only one copy on chromosome 2 was conserved. While the RIB 40 genome had additional copies of the alpha-amylase gene on chromosomes III, and V, 14160 had a second copy on chromosome II and an third copy on chromosome VI. Additionally, we identified hundreds of lineage specific genes, and putative high impact mutations in genes involved in secondary metabolism, including several of the core biosynthetic genes. Finally, to examine the functional effects of genome variation between strains, we measured amylase activity, proteolytic activity, and growth rate on several different substrates. RIB 40 produced significantly higher levels of amylase compared to 14160 when grown on rice and starch. Accordingly, RIB 40 grew faster on rice, while 14160 grew faster on soy. Taken together, our analyses reveal substantial genome and phenotypic variation within A. oryzae.


2021 ◽  
pp. 1-12
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt

Comparative neurobiologists have long wondered when and how the dorsal pallium (e.g., mammalian neocortex) evolved. For the last 50 years, the most widely accepted answer has been that this structure was already present in the earliest vertebrates and, therefore, homologous between the major vertebrate lineages. One challenge for this hypothesis is that the olfactory bulbs project throughout most of the pallium in the most basal vertebrate lineages (notably lampreys, hagfishes, and lungfishes) but do not project to the putative dorsal pallia in teleosts, cartilaginous fishes, and amniotes (i.e., reptiles, birds, and mammals). To make sense of these data, one may hypothesize that a dorsal pallium existed in the earliest vertebrates and received extensive olfactory input, which was subsequently lost in several lineages. However, the dorsal pallium is notoriously difficult to delineate in many vertebrates, and its homology between the various lineages is often based on little more than its topology. Therefore, we suspect that dorsal pallia evolved independently in teleosts, cartilaginous fishes, and amniotes. We further hypothesize that the emergence of these dorsal pallia was accompanied by the phylogenetic restriction of olfactory projections to the pallium and the expansion of inputs from other sensory modalities. We do not deny that the earliest vertebrates may have possessed nonolfactory sensory inputs to some parts of the pallium, but such projections alone do not define a dorsal pallium.


PhytoKeys ◽  
2021 ◽  
Vol 178 ◽  
pp. 17-30
Author(s):  
Quentin Groom ◽  
Sofie Meeus ◽  
Steven B. Janssens ◽  
Leen Leus ◽  
Ivan Hoste

Many species have been introduced beyond their native ranges and many have become global weeds. Human mediated dispersal has removed the geographic isolation of these species, reversing millions of years of independent evolution. Examples are the Oxalis species in section Corniculatae where several species have become invasive. Here we characterize and formally describe a hybrid between O. dillenii and O. corniculata, which occurs spontaneously in Belgium and Japan. Oxalis corniculata is probably native to Japan, but both species are alien to Belgium and O. dillenii is native to North America. We formally name this hybrid as Oxalis × vanaelstii. Although this hybrid is sterile, it is nevertheless vigorous and perennial. Both parent species grow as weeds in gardens; therefore, it is likely to be more common than currently appreciated in countries where these species co-occur.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1429
Author(s):  
Yang Teng ◽  
Jing Yang ◽  
Guofen Zhu ◽  
Fuli Gao ◽  
Yingying Han ◽  
...  

Detailed molecular genetic research on amphibian populations has a significant role in understanding the genetic adaptability to local environments. The oriental fire-bellied toads (Bombina orientalis) were artificially introduced to Beijing from Shandong Province in 1927, and since then, this separated population went through an independent evolution. To explore the differentiation of the introduced population with its original population, this study analyzed the genetic structure of the oriental fire-bellied toad, based on the mitochondrial genome control region and six microsatellite sites. The results showed that the haplotype diversity and nucleotide diversity of the mitochondrial D-loop region partial sequences of the Beijing Botanical Garden population and the Baiwangshan population were lower than those of the Shangdong Kunyushan population. Microsatellite marker analysis also showed that the observed heterozygosity and expected heterozygosity of the Beijing populations were lower than those of the Kunyushan population. The phylogenetic trees and network diagrams of haplotypes indicated that the three populations were not genetically separated. However, the structure analysis showed a genetic differentiation and categorized the sampling individuals into Beijing and Shandong genetic clusters, which indicated a tendency for isolated evolution in the Beijing population. Although the Beijing populations showed a decline in genetic diversity, it was still at a moderate level, which could maintain the survival of the population. Thus, there is no need to reintroduce new individuals from the Kunyushan source population.


2021 ◽  
Vol 31 (7) ◽  
pp. R328-R329
Author(s):  
Duckhyun Lhee ◽  
Debashish Bhattacharya ◽  
Hwan Su Yoon

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Deriba Abera ◽  
Caleb K. Kibet ◽  
Teshome Degefa ◽  
Lucas Amenga-Etego ◽  
Joel L. Bargul ◽  
...  

Abstract Background Plasmodium falciparum parasite populations in Ethiopia have been experiencing local selective pressures from drugs and immunity, leading to evolutionary adaptation. However, there was a paucity of data on genomic characterization and evolutionary adaptations of P. falciparum isolates from the central area of Ethiopia. Methods Whole-genome analysis of 25 P. falciparum isolates from central Ethiopia, specifically from West Arsi, were studied to determine their genetic diversity, population structures, and signatures of selection in known drug resistance alleles against global isolates from Cambodia, Thailand, DR Congo, and Malawi. Results A total of 18,517 high-quality single-nucleotide polymorphisms (SNPs) were identified in Ethiopian P. falciparum isolates. About 84% of the Ethiopian P. falciparum isolates had a FWS value > 0.95 showing a dominant single genotype infection in most isolates at the time of collection with little potential for out-crossing as expected in areas with low transmission intensity. Within-host diversity of Ethiopian infections was significantly different from East African (p < 0.001), but not Southeast Asian infections (P > 0.05). A significant population structure has been observed by PCA and population differentiation between Ethiopian parasites and East African (Fst ~ 10%) and Southeast Asian populations (Fst ~ 18%), suggesting limited gene flow and the independent evolution of the Ethiopian parasite population. Moreover, a total of 125 genes under balancing selection was found that include ama1, trap, eba175, and lsa3, previously identified as targets of human host immunity. Recent directional selection analysis using integrated standardized haplotype score (IHS) did not detect any selection signatures in the Pfcrt, Pfdhfr, Pfdhps, Pfmdr1, and PfK13 genes. However, known drug resistance-conferring mutations analysis showed that at least one SNP marker was fixed in these genes, but not in Pfdhps and PfK13. Conclusion Plasmodium falciparum populations in the central region of Ethiopia was structurally diverged from both Southeast Asian and other East African populations. Malaria infections in Ethiopia had low within-host diversity, and parasites carry fixed chloroquine resistance markers despite the withdrawal of this drug for the treatment of P. falciparum.


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