| 1. |
- Galbraith, James D., et al.
(författare)
-
Genome Stability Is in the Eye of the Beholder : CR1 Retrotransposon Activity Varies Significantly across Avian Diversity
- 2021
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 13:12
-
Tidskriftsartikel (refereegranskat)abstract
- Since the sequencing of the zebra finch genome it has become clear that avian genomes, while largely stable in terms of chromosome number and gene synteny, are more dynamic at an intrachromosomal level. A multitude of intrachromosomal rearrangements and significant variation in transposable element (TE) content have been noted across the avian tree. TEs are a source of genome plasticity, because their high similarity enables chromosomal rearrangements through nonallelic homologous recombination, and they have potential for exaptation as regulatory and coding sequences. Previous studies have investigated the activity of the dominant TE in birds, chicken repeat 1 (CR1) retrotransposons, either focusing on their expansion within single orders, or comparing passerines with nonpasserines. Here, we comprehensively investigate and compare the activity of CR1 expansion across orders of birds, finding levels of CR1 activity vary significantly both between and within orders. We describe high levels of TE expansion in genera which have speciated in the last 10 Myr including kiwis, geese, and Amazon parrots; low levels of TE expansion in songbirds across their diversification, and near inactivity of TEs in the cassowary and emu for millions of years. CR1s have remained active over long periods of time across most orders of neognaths, with activity at any one time dominated by one or two families of CR1 s. Our findings of higher TE activity in species -rich clades and dominant families of TEs within lineages mirror past findings in mammals and indicate that genome evolution in amniotes relies on universal TE-driven processes.
|
|
| 2. |
- Galbraith, James D., et al.
(författare)
-
New Environment, New Invaders-Repeated Horizontal Transfer of LINEs to Sea Snakes
- 2020
-
Ingår i: Genome Biology and Evolution. - : OXFORD UNIV PRESS. - 1759-6653. ; 12:12, s. 2370-2383
-
Tidskriftsartikel (refereegranskat)abstract
- Although numerous studies have found horizontal transposon transfer (HTT) to be widespread across metazoans, few have focused on HTT in marine ecosystems. To investigate potential recent HTTs into marine species, we searched for novel repetitive elements in sea snakes, a group of elapids which transitioned to a marine habitat at most 18 Ma. Our analysis uncovered repeated HTTs into sea snakes following their marine transition. The seven subfamilies of horizontally transferred LINE retrotransposons we identified in the olive sea snake (Aipysurus laevis) are transcribed, and hence are likely still active and expanding across the genome. A search of 600 metazoan genomes found all seven were absent from other amniotes, including terrestrial elapids, with the most similar LINEs present in fish and marine invertebrates. The one exception was a similar LINE found in sea kraits, a lineage of amphibious elapids which independently transitioned to a marine environment 25 Ma. Our finding of repeated horizontal transfer events into marine snakes greatly expands past findings that the marine environment promotes the transfer of transposons. Transposons are drivers of evolution as sources of genomic sequence and hence genomic novelty. We identified 13 candidate genes for HTT-induced adaptive change based on internal or neighboring HTT LINE insertions. One of these, ADCY4, is of particular interest as a part of the KEGG adaptation pathway "Circadian Entrainment." This provides evidence of the ecological interactions between species influencing evolution of metazoans not only through specific selection pressures, but also by contributing novel genomic material.
|
|
| 3. |
- Ottenburghs, Jente, et al.
(författare)
-
Genome Size Reduction and Transposon Activity Impact tRNA Gene Diversity While Ensuring Translational Stability in Birds
- 2021
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- As a highly diverse vertebrate class, bird species have adapted to various ecological systems. How this phenotypic diversity can be explained genetically is intensively debated and is likely grounded in differences in the genome content. Larger and more complex genomes could allow for greater genetic regulation that results in more phenotypic variety. Surprisingly, avian genomes are much smaller compared to other vertebrates but contain as many protein-coding genes as other vertebrates. This supports the notion that the phenotypic diversity is largely determined by selection on non-coding gene sequences. Transfer RNAs (tRNAs) represent a group of non-coding genes. However, the characteristics of tRNA genes across bird genomes have remained largely unexplored. Here, we exhaustively investigated the evolution and functional consequences of these crucial translational regulators with in bird species and across vertebrates. Our dense sampling of 55 avian genomes representing each bird order revealed an average of 169 tRNA genes with at least 31% being actively used. Unlike other vertebrates, avian tRNA genes are reduced in number and complexity but are still in line with vertebrate wobble pairing strategies and mutation-driven codon usage. Our detailed phylogenetic analyses further uncovered that new tRNA genes can emerge through multiplication by transposable elements. Together, this study provides the first comprehensive avian and cross-vertebrate tRNA gene analyses and demonstrates that tRNA gene evolution is flexible albeit constrained within functional boundaries of general mechanisms in protein translation.
|
|
| 4. |
- Platt, Roy N., II, et al.
(författare)
-
Targeted Capture of Phylogenetically Informative Ves SINE Insertions in Genus Myotis
- 2015
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 7:6, s. 1664-1675
-
Tidskriftsartikel (refereegranskat)abstract
- Identification of retrotransposon insertions in nonmodel taxa can be technically challenging and costly. This has inhibited progress in understanding retrotransposon insertion dynamics outside of a few well-studied species. To address this problem, we have extended a retrotransposon-based capture and sequence method (ME-Scan [mobile element scanning]) to identify insertions belonging to the Ves family of short interspersed elements (SINEs) across seven species of the bat genus Myotis. We identified between 120,000 and 143,000 SINE insertions in six taxa lacking a draft genome by comparing to the M. lucifugus reference genome. On average, eachVes insertion was sequenced to 129.6 x coverage. When mapped back to the M. lucifugus reference genome, all insertions were confidently assigned within a 10-bp window. Polymorphic Ves insertions were identified in each taxon based on their mapped locations. Using cross-species comparisons and the identified insertion positions, a presence-absence matrix was created for approximately 796,000 insertions. Dollo parsimony analysis of more than 85,000 phylogenetically informative insertions recovered strongly supported, monophyletic clades that correspond with the biogeography of each taxa. This phylogeny is similar to previously published mitochondrial phylogenies, with the exception of the placement of M. vivesi. These results support the utility of our variation on ME-Scan to identify polymorphic retrotransposon insertions in taxa without a reference genome and for large-scale retrotransposon-based phylogenetics.
|
|
| 5. |
- Sotero-Caio, Cibele G., et al.
(författare)
-
Evolution and Diversity of Transposable Elements in Vertebrate Genomes
- 2017
-
Ingår i: Genome Biology and Evolution. - : OXFORD UNIV PRESS. - 1759-6653. ; 9:1, s. 161-177
-
Tidskriftsartikel (refereegranskat)abstract
- Transposable elements (TEs) are selfish genetic elements that mobilize in genomes via transposition or retrotransposition and often make up large fractions of vertebrate genomes. Here, we review the current understanding of vertebrate TE diversity and evolution in the context of recent advances in genome sequencing and assembly techniques. TEs make up 4-60% of assembled vertebrate genomes, and deeply branching lineages such as ray-finned fishes and amphibians generally exhibit a higher TE diversity than the more recent radiations of birds and mammals. Furthermore, the list of taxa with exceptional TE landscapes is growing. We emphasize that the current bottleneck in genome analyses lies in the proper annotation of TEs and provide examples where superficial analyses led to misleading conclusions about genomeevolution. Finally, recent advances in long-read sequencing will soon permit access to TE-rich genomic regions that previously resisted assembly including the gigantic, TE-rich genomes of salamanders and lungfishes.
|
|
| 6. |
- Suh, Alexander, et al.
(författare)
-
Multiple Lineages of Ancient CR1 Retroposons Shaped the Early Genome Evolution of Amniotes
- 2015
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 7:1, s. 205-217
-
Tidskriftsartikel (refereegranskat)abstract
- Chicken repeat 1 (CR1) retroposons are long interspersed elements (LINEs) that are ubiquitous within amniote genomes and constitute the most abundant family of transposed elements in birds, crocodilians, turtles, and snakes. They are also present in mammalian genomes, where they reside as numerous relics of ancient retroposition events. Yet, despite their relevance for understanding amniote genome evolution, the diversity and evolution of CR1 elements has never been studied on an amniote-wide level. We reconstruct the temporal and quantitative activity of CR1 subfamilies via presence/absence analyses across crocodilian phylogeny and comparative analyses of 12 crocodilian genomes, revealing relative genomic stasis of retroposition during genome evolution of extant Crocodylia. Our large-scale phylogenetic analysis of amniote CR1 subfamilies suggests the presence of at least seven ancient CR1 lineages in the amniote ancestor; and amniote-wide analyses of CR1 successions and quantities reveal differential retention (presence of ancient relics or recent activity) of these CR1 lineages across amniote genome evolution. Interestingly, birds and lepidosaurs retained the fewest ancient CR1 lineages among amniotes and also exhibit smaller genome sizes. Our study is the first to analyze CR1 evolution in a genome-wide and amniote-wide context and the data strongly suggest that the ancestral amniote genome contained myriad CR1 elements from multiple ancient lineages, and remnants of these are still detectable in the relatively stable genomes of crocodilians and turtles. Early mammalian genome evolution was thus characterized by a drastic shift from CR1 prevalence to dominance and hyperactivity of L2 LINEs in monotremes and L1 LINEs in therians.
|
|
| 7. |
- Suh, Alexander, et al.
(författare)
-
New Perspectives on the Evolution of Within-Individual Genome Variation and Germline/Soma Distinction
- 2021
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 13:6
-
Tidskriftsartikel (refereegranskat)abstract
- Genomes can vary significantly even within the same individual. The underlying mechanisms are manifold, ranging from somatic mutation and recombination, development-associated ploidy changes and genetic bottlenecks, over to programmed DNA elimination during germline/soma differentiation. In this perspective piece, we briefly reviewrecent developments in the study ofwithinindividual genome variation in eukaryotes and prokaryotes. We highlight a Society forMolecular Biology and Evolution 2020 virtual symposium entitled "Within-individual genome variation and germline/soma distinction" and the present Special Section of the same name in Genome Biology and Evolution, together fostering cross-taxon synergies in the field to identify and tackle key open questions in the understanding of within-individual genome variation.
|
|
| 8. |
- Talla, Venkat, et al.
(författare)
-
Rapid Increase in Genome Size as a Consequence of Transposable Element Hyperactivity in Wood-White (Leptidea) Butterflies
- 2017
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 9:10, s. 2491-2505
-
Tidskriftsartikel (refereegranskat)abstract
- Characterizing and quantifying genome size variation among organisms and understanding if genome size evolves as a consequence of adaptive or stochastic processes have been long-standing goals in evolutionary biology. Here, we investigate genome size variation and association with transposable elements (TEs) across lepidopteran lineages using a novel genome assembly of the common wood-white (Leptidea sinapis) and population re-sequencing data from both L. sinapis and the closely related L. reali and L. juvernica together with 12 previously available lepidopteran genome assemblies. A phylogenetic analysis confirms established relationships among species, but identifies previously unknown intraspecific structure within Leptidea lineages. The genome assembly of L. sinapis is one of the largest of any lepidopteran taxon so far (643Mb) and genome size is correlated with abundance of TEs, both in Lepidoptera in general and within Leptidea where L. juvernica from Kazakhstan has considerably larger genome size than any other Leptidea population. Specific TE subclasses have been active in different Lepidoptera lineages with a pronounced expansion of predominantly LINEs, DNA elements, and unclassified TEs in the Leptidea lineage after the split from other Pieridae. The rate of genome expansion in Leptidea in general has been in the range of four Mb/Million year (My), with an increase in a particular L. juvernica population to 72Mb/My. The considerable differences in accumulation rates of specific TE classes in different lineages indicate that TE activity plays a major role in genome size evolution in butterflies and moths.
|
|
| 9. |
- Zheng, Wanjing, et al.
(författare)
-
Different Host-Endogenous Retrovirus Relationships between Mammals and Birds Reflected in Genome-Wide Evolutionary Interaction Patterns
- 2024
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 16:4
-
Tidskriftsartikel (refereegranskat)abstract
- Mammals and birds differ largely in their average endogenous retrovirus loads, namely the proportion of endogenous retrovirus in the genome. The host-endogenous retrovirus relationships, including conflict and co-option, have been hypothesized among the causes of this difference. However, there has not been studies about the genomic evolutionary signal of constant host-endogenous retrovirus interactions in a long-term scale and how such interactions could lead to the endogenous retrovirus load difference. Through a phylogeny-controlled correlation analysis on similar to 5,000 genes between the dN/dS ratio of each gene and the load of endogenous retrovirus in 12 mammals and 21 birds, separately, we detected genes that may have evolved in association with endogenous retrovirus loads. Birds have a higher proportion of genes with strong correlation between dN/dS and the endogenous retrovirus load than mammals. Strong evidence of association is found between the dN/dS of the coding gene for leucine-rich repeat-containing protein 23 and endogenous retrovirus load in birds. Gene set enrichment analysis shows that gene silencing rather than immunity and DNA recombination may have a larger contribution to the association between dN/dS and the endogenous retrovirus load for both mammals and birds. The above results together showing different evolutionary patterns between bird and mammal genes can partially explain the apparently lower endogenous retrovirus loads of birds, while gene silencing may be a universal mechanism that plays a remarkable role in the evolutionary interaction between the host and endogenous retrovirus. In summary, our study presents signals that the host genes might have driven or responded to endogenous retrovirus load changes in long-term evolution.
|
|
