Rapid Evolution of Horse Satellite DNA

Genomics ◽  
1993 ◽  
Vol 18 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Edwin R. Wijers ◽  
Carla Zijlstra ◽  
Johannes A. Lenstra
Keyword(s):  
Satellite Dna ◽  
Rapid Evolution

scholarly journals Cross-species incompatibility between a DNA satellite and a chromatin protein poisons germline genome integrity

2021 ◽  
Author(s):  
Cara L Brand ◽  
Mia T Levine
Keyword(s):  
Satellite Dna ◽  
Rapid Evolution ◽  
Genome Integrity ◽  
Dna Repeats ◽  
Chromatin Protein ◽  
Genetic Rescue ◽  
Chromatin Proteins ◽  
Genomic Regions ◽  
Female Germline ◽  
Nuclear Processes

Satellite DNA spans megabases of eukaryotic genome sequence. These vast stretches of tandem DNA repeats undergo high rates of sequence turnover, resulting in radically different satellite DNA landscapes between closely related species. Such extreme evolutionary plasticity suggests that satellite DNA accumulates mutations with no functional consequence. Paradoxically, satellite-rich genomic regions support essential, conserved nuclear processes, including chromosome segregation, dosage compensation, and nuclear structure. A leading resolution to this paradox is that deleterious alterations to satellite DNA trigger adaptive evolution of chromatin proteins to preserve these essential functions. Here we experimentally test this model of coevolution between chromatin proteins and DNA satellites by conducting an evolution-guided manipulation of both protein and satellite. We focused on an adaptively evolving, ovary-enriched chromatin protein, called Maternal Haploid (MH) from Drosophila. MH co-localizes with an 11 Mb 359-bp satellite array present in Drosophila melanogaster but absent in its sister species, D. simulans. Using CRISPR/Cas9-mediated transgenesis, we swapped the D. simulans version of MH into D. melanogaster. We discovered that D. melanogaster females encoding only the D. simulans mh (mh[sim]) do not phenocopy the mh null mutation. Instead, MH[sim] is toxic to D. melanogaster ovaries: we observed elevated ovarian cell death, reduced ovary size, and subfertility in mh[sim] females. Using both cell biological and genetic approaches, we demonstrate that MH[sim] poisons oogenesis through a DNA damage pathway. Remarkably, deleting the D. melanogaster-specific 359 satellite array from mh[sim] females completely restores female germline genome integrity and fertility. This genetic rescue offers experimental evidence that rapid evolution resulted in a cross-species incompatibility between the 359 satellite and MH. These data suggest that coevolution between ostensibly inert repetitive DNA and essential chromatin proteins preserves germline genome integrity.

scholarly journals Selection constrains high rates of satellite DNA mutation in Daphnia pulex

2017 ◽  
Author(s):  
Jullien M. Flynn ◽  
Ian Caldas ◽  
Melania E. Cristescu ◽  
Andrew G. Clark
Keyword(s):  
Satellite Dna ◽  
Related Species ◽  
Rapid Evolution ◽  
Daphnia Pulex ◽  
Selective Constraint ◽  
Mutation Rates ◽  
Stabilizing Selection ◽  
Closely Related Species ◽  
Dna Mutation ◽  
Evolutionary Forces

AbstractA long-standing evolutionary puzzle is that all eukaryotic genomes contain large amounts of tandemly-repeated satellite DNA whose composition varies greatly among even closely related species. To elucidate the evolutionary forces governing satellite dynamics, quantification of the rates and patterns of mutations in satellite DNA copy number and tests of its selective neutrality are necessary. Here we used whole-genome sequences of 28 mutation accumulation (MA) lines of Daphnia pulex in addition to six isolates from a non-MA population originating from the same progenitor to both estimate mutation rates of abundances of satellite sequences and evaluate the selective regime acting upon them. We found that mutation rates of individual satellite sequence “kmers” were both high and highly variable, ranging from additions/deletions of 0.29 – 105 copies per generation (reflecting changes of 0.12 - 0.80 percent per generation). Our results also provide evidence that new kmer sequences are often formed from existing ones. The non-MA population isolates showed a signal of either purifying or stabilizing selection, with 33 % lower variation in kmer abundance on average than the MA lines, although the level of selective constraint was not evenly distributed across all kmers. The changes between many pairs of kmers were correlated, and the pattern of correlations was significantly different between the MA lines and the non-MA population. Our study demonstrates that kmer sequences can experience extremely rapid evolution in abundance, which can lead to high levels of divergence in genome-wide satellite DNA composition between closely related species.

scholarly journals Diversity of PBI-DdeI satellite DNA in snakes correlates with rapid independent evolution and different functional roles

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ratchaphol Thongchum ◽  
Worapong Singchat ◽  
Nararat Laopichienpong ◽  
Panupong Tawichasri ◽  
Ekaphan Kraichak ◽  
...  
Keyword(s):  
Satellite Dna ◽  
Copy Number ◽  
Rapid Evolution ◽  
Chromosomal Distribution ◽  
Functional Roles ◽  
Network Analyses ◽  
Naja Kaouthia ◽  
Slow Evolution ◽  
Python Bivittatus ◽  
Species Specific

Abstract To better understand PBI-DdeI satellite DNA located in the centromeric region of python, molecular evolution analysis was conducted on 40 snake species. A ladder-like pattern of DNA bands with repetition of the 194–210 bp monomer was observed in 15 species using PCR. Molecular cloning was performed to obtain 97 AT-rich monomer sequences. Phylogenetic and network analyses showed three PBI-DdeI subfamilies with sequences grouped in species-specific clusters, suggesting rapid evolution. Slow evolution was found in eight species with shared PBI-DdeI sequences, suggesting recent species diversification, allowing PBI-DdeI no time to diverge, with limited homogenization and fixation processes. Quantitative real-time PCR showed large differences in copy number between Python bivittatus and other snakes, consistent with repeat scanning of whole genome sequences. Copy numbers were significantly higher in female Naja kaouthia than in males, concurring with chromosomal distribution of PBI-DdeI specifically localized to female W chromosomes. PBI-DdeI might act as an evolutionary driver with several repeats to promote W chromosome differentiation and heterochromatinization in N. kaouthia. Analysis revealed PBI-DdeI with a reduced copy number, compared to P. bivittatus, in most snakes studied, and it is possible that it subsequently dispersed and amplified on W chromosomes with different functional roles in N. kaouthia.

scholarly journals Too much too many: comparative analysis of morabine grasshopper genomes reveals highly abundant transposable elements and rapidly proliferating satellite DNA repeats

2020 ◽  
Author(s):  
Octavio M. Palacios-Gimenez ◽  
Julia Koelman ◽  
Marc Palmada Flores ◽  
Tessa M. Bradford ◽  
Karl K. Jones ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Genome Evolution ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Species Complex ◽  
Rapid Evolution ◽  
Dna Repeats ◽  
Large Genome ◽  
Chromosomal Races

BackgroundThe repeatome, the collection of repetitive DNA sequences represented by transposable elements (TEs) and tandemly repeated satellite DNA (satDNAs), is found in high proportion in organisms across the tree of life. Grasshoppers have large genomes (average 9 Gb), containing large amounts of repetitive DNA which has hampered progress in assembling reference genomes. Here we combined linked-read genomics with transcriptomics to assemble, characterize, and compare the structure of the repeatome and its contribution to genome evolution, in four chromosomal races of the morabine grasshopper Vandiemenella viatica species complex.ResultsWe obtained linked-read genome assemblies of 2.73-3.27 Gb from estimated genome sizes of 4.26-5.07 Gb DNA per haploid genome of the four chromosomal races of V. viatica. These constitute the third largest insect genomes assembled so far (the largest being two locust grasshoppers). Combining complementary annotation tools and manual curation, we found a large diversity of TEs and satDNAs constituting 66 to 75 % per genome assembly. A comparison of sequence divergence within the TE classes revealed massive accumulation of recent TEs in all four races (314-463 Mb per assembly), indicating that their large genome size is likely due to similar rates of TE accumulation across the four races. Transcriptome sequencing showed more biased TE expression in reproductive tissues than somatic tissues, implying permissive transcription in gametogenesis. Out of 129 satDNA families, 102 satDNA families were shared among the four chromosomal races, which likely represent a repertoire of satDNA families in the ancestor of the V. viatica chromosomal races. Notably, 50 of these shared satDNA families underwent differential proliferation since the recent diversification of the V. viatica species complex.ConclusionIn-depth annotation of the repeatome in morabine grasshoppers provided new insights into the genome evolution of Orthoptera. Our TEs analysis revealed a massive recent accumulation of TEs equivalent to the size of entire Drosophila genomes, which likely explains the large genome sizes in grasshoppers. Although the TE and satDNA repertoires were rather similar between races, the patterns of TE expression and satDNA proliferation suggest rapid evolution of grasshopper genomes on recent timescales.

scholarly journals Defective satellite DNA clustering into chromocenters underlies hybrid incompatibility in Drosophila

2021 ◽  
Author(s):  
Madhav Jagannathan ◽  
Yukiko M Yamashita
Keyword(s):  
Satellite Dna ◽  
Rapid Evolution ◽  
Dna Binding Proteins ◽  
Dna Repeats ◽  
Hybrid Cells ◽  
Entire Genome ◽  
Closely Related Species ◽  
Hybrid Incompatibility ◽  
Cluster Satellite ◽  
Single Nucleus

Although rapid evolution of pericentromeric satellite DNA repeats is theorized to promote hybrid incompatibility (HI), how divergent repeats affect hybrid cells remains poorly understood. Recently, we demonstrated that sequence-specific DNA-binding proteins cluster satellite DNA from multiple chromosomes into chromocenters, thereby bundling chromosomes to maintain the entire genome in a single nucleus. Here we show that ineffective clustering of divergent satellite DNA in the cells of Drosophila hybrids results in chromocenter disruption, associated micronuclei formation and tissue atrophy. We further demonstrate that previously identified HI factors trigger chromocenter disruption and micronuclei in hybrids, linking their function to a conserved cellular process. Together, we propose a unifying framework that explains how the widely observed satellite DNA divergence between closely related species can cause reproductive isolation.

The Glissonian Approach of the Hilum

Swiss Surgery ◽  
1999 ◽  
Vol 5 (3) ◽  
pp. 143-146 ◽  
Author(s):  
Launois ◽  
Maddern ◽  
Tay
Keyword(s):  
Portal Vein ◽  
Hepatic Artery ◽  
Posterior Approach ◽  
Hepatic Duct ◽  
Rapid Evolution ◽  
Hepatic Tissue ◽  
Detailed Knowledge ◽  
Porta Hepatis ◽  
Liver Segment ◽  
Glissonian Approach

The detailed knowledge of the segmental anatomy of the liver has led to a rapid evolution in resectional surgery based on the intrahepatic distribution of the portal trinity (the hepatic artery, hepatic duct and portal vein). The classical intrafascial or extrahepatic approach is to isolate the appropriate branch of the portal vein, hepatic artery and the hepatic duct, outside the liver substance. Another method, the extrafascial approach, is to dissect the whole sheath of the pedicle directly after division of a substantial amount of the hepatic tissue to reach the pedicle, which is surrounded by a sheath, derived from Glisson's capsule. This Glissonian sheath encloses the portal trinity. In the transfissural or intrahepatic approach, these sheaths can be approached either anteriorly (after division of the main, right or umbilical fissure) or posteriorly from behind the porta hepatis. We describe the technique for approaching the Glissonian sheath and hence the hepatic pedicle structures and their branches by the intrahepatic posterior approach that allows early delineation of the liver segment without the need for ancillary techniques. In addition, the indications for the use of this technique in the technical and oncologic settings are also discussed.

Gayet-Wernicke encephalopathy with rapid evolution toward dementia in alcoholic dependence – case report

Psihiatru ro ◽  
2019 ◽  
Vol 58 (3) (1) ◽  
pp. 18-20
Author(s):  
Cătălina Crişan ◽  
Laura Grosu ◽  
Oana Vanţa
Keyword(s):  
Case Report ◽  
Thiamine Deficiency ◽  
Withdrawal Syndrome ◽  
Rapid Evolution ◽  
Full Recovery ◽  
Wernicke Encephalopathy ◽  
Korsakoff Syndrome ◽  
Dementia Syndrome ◽  
Patients Experience

Gayet-Wernicke encephalopathy is an acute neuropsychiatric condition caused by thiamine deficiency. Only a small percentage of patients experience all three symptoms, with ophtalmoplegia, ataxia and confusion, and the full triad occurs more frequently among those who have overused alcohol. The evolution is toward full recovery, Korsakoff syndrome, dementia or death. We present the case of a 56-year-old patient, known with a diagnostic of alcoholism, who was admitted for a complicated withdrawal syndrome with delirium and who developed encephalopathy and dementia syndrome.

Sign in / Sign up

Export Citation Format

Share Document