scholarly journals From de novo to ‘de nono’: The majority of novel protein coding genes identified with phylostratigraphy are old genes or recent duplicates

Author(s):  
Claudio Casola
2019 ◽  
Author(s):  
Nikolaos Vakirlis ◽  
Omer Acar ◽  
Brian Hsu ◽  
Nelson Castilho Coelho ◽  
S. Branden Van Oss ◽  
...  

SummaryRecent evidence demonstrates that novel protein-coding genes can arisede novofrom intergenic loci. This evolutionary innovation is thought to be facilitated by the pervasive translation of intergenic transcripts, which exposes a reservoir of variable polypeptides to natural selection. Do intergenic translation events yield polypeptides with useful biochemical capacities? The answer to this question remains controversial. Here, we systematically characterized howde novoemerging coding sequences impact fitness. In budding yeast, overexpression of these sequences was enriched in beneficial effects, while their disruption was generally inconsequential. We found that beneficial emerging sequences have a strong tendency to encode putative transmembrane proteins, which appears to stem from a cryptic propensity for transmembrane signals throughout thymine-rich intergenic regions of the genome. These findings suggest that novel genes with useful biochemical capacities, such as transmembrane domains, tend to evolvede novowithin intergenic loci that already harbored a blueprint for these capacities.


2018 ◽  
Author(s):  
Claudio Casola

AbstractThe evolution of novel protein-coding genes from noncoding regions of the genome is one of the most compelling evidence for genetic innovations in nature. One popular approach to identify de novo genes is phylostratigraphy, which consists of determining the approximate time of origin (age) of a gene based on its distribution along a species phylogeny. Several studies have revealed significant flaws in determining the age of genes, including de novo genes, using phylostratigraphy alone. However, the rate of false positives in de novo gene surveys, based on phylostratigraphy, remains unknown. Here, I re-analyze the findings from three studies, two of which identified tens to hundreds of rodent-specific de novo genes adopting a phylostratigraphy-centered approach. Most of the putative de novo genes discovered in these investigations are no longer included in recently updated mouse gene sets. Using a combination of synteny information and sequence similarity searches, I show that about 60% of the remaining 381 putative de novo genes share homology with genes from other vertebrates, originated through gene duplication, and/or share no synteny information with non-rodent mammals. These results led to an estimated rate of ∼12 de novo genes per million year in mouse. Contrary to a previous study (Wilson et al. 2017), I found no evidence supporting the preadaptation hypothesis of de novo gene formation. Nearly half of the de novo genes confirmed in this study are within older genes, indicating that co-option of preexisting regulatory regions and a higher GC content may facilitate the origin of novel genes.


2015 ◽  
Vol 370 (1678) ◽  
pp. 20140332 ◽  
Author(s):  
Aoife McLysaght ◽  
Daniele Guerzoni

The origin of novel protein-coding genes de novo was once considered so improbable as to be impossible. In less than a decade, and especially in the last five years, this view has been overturned by extensive evidence from diverse eukaryotic lineages. There is now evidence that this mechanism has contributed a significant number of genes to genomes of organisms as diverse as Saccharomyces , Drosophila , Plasmodium , Arabidopisis and human. From simple beginnings, these genes have in some instances acquired complex structure, regulated expression and important functional roles. New genes are often thought of as dispensable late additions; however, some recent de novo genes in human can play a role in disease. Rather than an extremely rare occurrence, it is now evident that there is a relatively constant trickle of proto-genes released into the testing ground of natural selection. It is currently unknown whether de novo genes arise primarily through an ‘RNA-first’ or ‘ORF-first’ pathway. Either way, evolutionary tinkering with this pool of genetic potential may have been a significant player in the origins of lineage-specific traits and adaptations.


2019 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog

ABSTRACTThe Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromere, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.


2021 ◽  
Author(s):  
VISHNU PRASOODANAN P K ◽  
Shruti S. Menon ◽  
Rituja Saxena ◽  
Prashant Waiker ◽  
Vineet K Sharma

Discovery of novel thermophiles has shown promising applications in the field of biotechnology. Due to their thermal stability, they can survive the harsh processes in the industries, which make them important to be characterized and studied. Members of Anoxybacillus are alkaline tolerant thermophiles and have been extensively isolated from manure, dairy-processed plants, and geothermal hot springs. This article reports the assembled data of an aerobic bacterium Anoxybacillus sp. strain MB8, isolated from the Tattapani hot springs in Central India, where the 16S rRNA gene shares an identity of 97% (99% coverage) with Anoxybacillus kamchatkensis strain G10. The de novo assembly and annotation performed on the genome of Anoxybacillus sp. strain MB8 comprises of 2,898,780 bp (in 190 contigs) with a GC content of 41.8% and includes 2,976 protein-coding genes,1 rRNA operon, 73 tRNAs, 1 tm-RNA and 10 CRISPR arrays. The predicted protein-coding genes have been classified into 21 eggNOG categories. The KEGG Automated Annotation Server (KAAS) analysis indicated the presence of assimilatory sulfate reduction pathway, nitrate reducing pathway, and genes for glycoside hydrolases (GHs) and glycoside transferase (GTs). GHs and GTs hold widespread applications, in the baking and food industry for bread manufacturing, and in the paper, detergent and cosmetic industry. Hence, Anoxybacillus sp. strain MB8 holds the potential to be screened and characterized for such commercially relevant enzymes.


2019 ◽  
Author(s):  
Joanna Kaplanis ◽  
Kaitlin E. Samocha ◽  
Laurens Wiel ◽  
Zhancheng Zhang ◽  
Kevin J. Arvai ◽  
...  

SummaryDe novo mutations (DNMs) in protein-coding genes are a well-established cause of developmental disorders (DD). However, known DD-associated genes only account for a minority of the observed excess of such DNMs. To identify novel DD-associated genes, we integrated healthcare and research exome sequences on 31,058 DD parent-offspring trios, and developed a simulation-based statistical test to identify gene-specific enrichments of DNMs. We identified 285 significantly DD-associated genes, including 28 not previously robustly associated with DDs. Despite detecting more DD-associated genes than in any previous study, much of the excess of DNMs of protein-coding genes remains unaccounted for. Modelling suggests that over 1,000 novel DD-associated genes await discovery, many of which are likely to be less penetrant than the currently known genes. Research access to clinical diagnostic datasets will be critical for completing the map of dominant DDs.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10364
Author(s):  
Natalia I. Abramson ◽  
Fedor N. Golenishchev ◽  
Semen Yu. Bodrov ◽  
Olga V. Bondareva ◽  
Evgeny A. Genelt-Yanovskiy ◽  
...  

In this article, we present the nearly complete mitochondrial genome of the Subalpine Kashmir vole Hyperacrius fertilis (Arvicolinae, Cricetidae, Rodentia), assembled using data from Illumina next-generation sequencing (NGS) of the DNA from a century-old museum specimen. De novo assembly consisted of 16,341 bp and included all mitogenome protein-coding genes as well as 12S and 16S RNAs, tRNAs and D-loop. Using the alignment of protein-coding genes of 14 previously published Arvicolini tribe mitogenomes, seven Clethrionomyini mitogenomes, and also Ondatra and Dicrostonyx outgroups, we conducted phylogenetic reconstructions based on a dataset of 13 protein-coding genes (PCGs) under maximum likelihood and Bayesian inference. Phylogenetic analyses robustly supported the phylogenetic position of this species within the tribe Arvicolini. Among the Arvicolini, Hyperacrius represents one of the early-diverged lineages. This result of phylogenetic analysis altered the conventional view on phylogenetic relatedness between Hyperacrius and Alticola and prompted the revision of morphological characters underlying the former assumption. Morphological analysis performed here confirmed molecular data and provided additional evidence for taxonomic replacement of the genus Hyperacrius from the tribe Clethrionomyini to the tribe Arvicolini.


2019 ◽  
Vol 42 (4) ◽  
pp. 601-611 ◽  
Author(s):  
Yan Li ◽  
Liukun Jia ◽  
Zhihua Wang ◽  
Rui Xing ◽  
Xiaofeng Chi ◽  
...  

Abstract Saxifraga sinomontana J.-T. Pan & Gornall belongs to Saxifraga sect. Ciliatae subsect. Hirculoideae, a lineage containing ca. 110 species whose phylogenetic relationships are largely unresolved due to recent rapid radiations. Analyses of complete chloroplast genomes have the potential to significantly improve the resolution of phylogenetic relationships in this young plant lineage. The complete chloroplast genome of S. sinomontana was de novo sequenced, assembled and then compared with that of other six Saxifragaceae species. The S. sinomontana chloroplast genome is 147,240 bp in length with a typical quadripartite structure, including a large single-copy region of 79,310 bp and a small single-copy region of 16,874 bp separated by a pair of inverted repeats (IRs) of 25,528 bp each. The chloroplast genome contains 113 unique genes, including 79 protein-coding genes, four rRNAs and 30 tRNAs, with 18 duplicates in the IRs. The gene content and organization are similar to other Saxifragaceae chloroplast genomes. Sixty-one simple sequence repeats were identified in the S. sinomontana chloroplast genome, mostly represented by mononucleotide repeats of polyadenine or polythymine. Comparative analysis revealed 12 highly divergent regions in the intergenic spacers, as well as coding genes of matK, ndhK, accD, cemA, rpoA, rps19, ndhF, ccsA, ndhD and ycf1. Phylogenetic reconstruction of seven Saxifragaceae species based on 66 protein-coding genes received high bootstrap support values for nearly all identified nodes, suggesting a promising opportunity to resolve infrasectional relationships of the most species-rich section Ciliatae of Saxifraga.


2020 ◽  
Vol 10 (3) ◽  
pp. 891-897 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog

The Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193 Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromeres, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.


2020 ◽  
Vol 110 (9) ◽  
pp. 1503-1506
Author(s):  
Olufemi A. Akinsanmi ◽  
Lilia C. Carvalhais

Pseudocercospora macadamiae causes husk spot in macadamia in Australia. Lack of genomic resources for this pathogen has restricted acquiring knowledge on the mechanism of disease development, spread, and its role in fruit abscission. To address this gap, we sequenced the genome of P. macadamiae. The sequence was de novo assembled into a draft genome of 40 Mb, which is comparable to closely related species in the family Mycosphaerellaceae. The draft genome comprises 212 scaffolds, of which 99 scaffolds are over 50 kb. The genome has a 49% GC content and is predicted to contain 15,430 protein-coding genes. This draft genome sequence is the first for P. macadamiae and represents a valuable resource for understanding genome evolution and plant disease resistance.


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