gene evolution
Dotaz
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sv.
- MeSH
- genom lidský MeSH
- geny genetika MeSH
- molekulární biologie MeSH
- molekulární evoluce MeSH
- rekombinace genetická MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Obecná genetika. Obecná cytogenetika. Evoluce
- NLK Obory
- genetika, lékařská genetika
Lateral gene transfer (LGT) is an important mechanism of evolution for protists adapting to oxygen-poor environments. Specifically, modifications of energy metabolism in anaerobic forms of mitochondria (e.g., hydrogenosomes) are likely to have been associated with gene transfer from prokaryotes. An interesting question is whether the products of transferred genes were directly targeted into the ancestral organelle or initially operated in the cytosol and subsequently acquired organelle-targeting sequences. Here, we identified key enzymes of hydrogenosomal metabolism in the free-living anaerobic amoebozoan Mastigamoeba balamuthi and analyzed their cellular localizations, enzymatic activities, and evolutionary histories. Additionally, we characterized 1) several canonical mitochondrial components including respiratory complex II and the glycine cleavage system, 2) enzymes associated with anaerobic energy metabolism, including an unusual D-lactate dehydrogenase and acetyl CoA synthase, and 3) a sulfate activation pathway. Intriguingly, components of anaerobic energy metabolism are present in at least two gene copies. For each component, one copy possesses an mitochondrial targeting sequence (MTS), whereas the other lacks an MTS, yielding parallel cytosolic and hydrogenosomal extended glycolysis pathways. Experimentally, we confirmed that the organelle targeting of several proteins is fully dependent on the MTS. Phylogenetic analysis of all extended glycolysis components suggested that these components were acquired by LGT. We propose that the transformation from an ancestral organelle to a hydrogenosome in the M. balamuthi lineage involved the lateral acquisition of genes encoding extended glycolysis enzymes that initially operated in the cytosol and that established a parallel hydrogenosomal pathway after gene duplication and MTS acquisition.
- MeSH
- anaerobióza genetika MeSH
- Archamoebae enzymologie genetika metabolismus MeSH
- duplikace genu * MeSH
- energetický metabolismus genetika MeSH
- enzymy genetika izolace a purifikace MeSH
- molekulární evoluce * MeSH
- organely enzymologie genetika metabolismus MeSH
- přenos genů horizontální * MeSH
- struktury buněčné membrány genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
... molecular genetics -- Genetics as a key to human origins and prehistory -- Fundamentals of human evolution ... ... : mutation and natural selection -- Fundamentals of human evolution : drift, migration, and quantitative ... ... analysis of human genetic diversity -- Cultural evolution -- Geography of human genes and correlation ... ... transition in Europe and the peopling of the Americas -- Genes, kinship, and human identity -- Cultural ... ... clines, clades, cycles, and waves -- Genes and culture in medicine. ...
xxi, 314 s., [12] s. tab. : il., tab. ; 25 cm
- MeSH
- biologická evoluce MeSH
- genetické jevy MeSH
- kulturní evoluce MeSH
- paleontologie MeSH
- populační genetika MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Obecná genetika. Obecná cytogenetika. Evoluce
- NLK Obory
- genetika, lékařská genetika
- biologie
1st ed. xv, 237 s.
- Konspekt
- Obecná genetika. Obecná cytogenetika. Evoluce
- NLK Obory
- genetika, lékařská genetika
- biologie
- botanika
BACKGROUND: The evolution of sex chromosomes is often accompanied by gene or chromosome rearrangements. Recently, the gene AP3 was characterized in the dioecious plant species Silene latifolia. It was suggested that this gene had been transferred from an autosome to the Y chromosome. RESULTS: In the present study we provide evidence for the existence of an X linked copy of the AP3 gene. We further show that the Y copy is probably located in a chromosomal region where recombination restriction occurred during the first steps of sex chromosome evolution. A comparison of X and Y copies did not reveal any clear signs of degenerative processes in exon regions. Instead, both X and Y copies show evidence for relaxed selection compared to the autosomal orthologues in S. vulgaris and S. conica. We further found that promoter sequences differ significantly. Comparison of the genic region of AP3 between the X and Y alleles and the corresponding autosomal copies in the gynodioecious species S. vulgaris revealed a massive accumulation of retrotransposons within one intron of the Y copy of AP3. Analysis of the genomic distribution of these repetitive elements does not indicate that these elements played an important role in the size increase characteristic of the Y chromosome. However, in silico expression analysis shows biased expression of individual domains of the identified retroelements in male plants. CONCLUSIONS: We characterized the structure and evolution of AP3, a sex linked gene with copies on the X and Y chromosomes in the dioecious plant S. latifolia. These copies showed complementary expression patterns and relaxed evolution at protein level compared to autosomal orthologues, which suggests subfunctionalization. One intron of the Y-linked allele was invaded by retrotransposons that display sex-specific expression patterns that are similar to the expression pattern of the corresponding allele, which suggests that these transposable elements may have influenced evolution of expression patterns of the Y copy. These data could help researchers decipher the role of transposable elements in degenerative processes during sex chromosome evolution.
- MeSH
- alely MeSH
- chromozomy rostlin genetika MeSH
- DNA rostlinná genetika MeSH
- exony MeSH
- introny MeSH
- molekulární evoluce MeSH
- promotorové oblasti (genetika) MeSH
- regulace genové exprese u rostlin MeSH
- repetitivní sekvence nukleových kyselin MeSH
- retroelementy MeSH
- rostlinné geny MeSH
- rostlinné proteiny genetika MeSH
- sekvenční analýza DNA MeSH
- Silene genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Transposable elements (TEs) are able to jump to new locations (transposition) in the genome, usually after replication. They constitute the so-called selfish or junk DNA and take over large proportions of some genomes. Due to their ability to move around they can change the DNA landscape of genomes and are therefore a rich source of innovation in genes and gene regulation. Surge of sequence data in the past years has significantly facilitated large scale comparative studies. Cephalochordates have been regarded as a useful proxy to ancestral chordate condition partially due to the comparatively slow evolutionary rate at morphological and genomic level. In this study, we used opsin gene family from three Branchiostoma species as a window into cephalochordate genome evolution. We compared opsin complements in terms of family size, gene structure and sequence allowing us to identify gene duplication and gene loss events. Furthermore, analysis of the opsin containing genomic loci showed that they are populated by TEs. In summary, we provide evidence of the way transposable elements may have contributed to the evolution of opsin gene family and to the shaping of cephalochordate genomes in general.
Strigolactones (SLs) are a relatively recent addition to the list of plant hormones that control different aspects of plant development. SL signalling is perceived by an α/β hydrolase, DWARF 14 (D14). A close homolog of D14, KARRIKIN INSENSTIVE2 (KAI2), is involved in perception of an uncharacterized molecule called karrikin (KAR). Recent studies in Arabidopsis identified the SUPPRESSOR OF MAX2 1 (SMAX1) and SMAX1-LIKE 7 (SMXL7) to be potential SCF-MAX2 complex-mediated proteasome targets of KAI2 and D14, respectively. Genetic studies on SMXL7 and SMAX1 demonstrated distinct developmental roles for each, but very little is known about these repressors in terms of their sequence features. In this study, we performed an extensive comparative analysis of SMXLs and determined their phylogenetic and evolutionary history in the plant lineage. Our results show that SMXL family members can be sub-divided into four distinct phylogenetic clades/classes, with an ancient SMAX1. Further, we identified the clade-specific motifs that have evolved and that might act as determinants of SL-KAR signalling specificity. These specificities resulted from functional diversities among the clades. Our results suggest that a gradual co-evolution of SMXL members with their upstream receptors D14/KAI2 provided an increased specificity to both the SL perception and response in land plants.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- laktony metabolismus MeSH
- molekulární evoluce * MeSH
- multigenová rodina * MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
