Meiotic recombination is a critical process for plant breeding, as it creates novel allele combinations that can be exploited for crop improvement. In wheat, a complex allohexaploid that has a diploid-like behaviour, meiotic recombination between homoeologous or alien chromosomes is suppressed through the action of several loci. Here, we report positional cloning of Pairing homoeologous 2 (Ph2) and functional validation of the wheat DNA mismatch repair protein MSH7-3D as a key inhibitor of homoeologous recombination, thus solving a half-century-old question. Similar to ph2 mutant phenotype, we show that mutating MSH7-3D induces a substantial increase in homoeologous recombination (up to 5.5 fold) in wheat-wild relative hybrids, which is also associated with a reduction in homologous recombination. These data reveal a role for MSH7-3D in meiotic stabilisation of allopolyploidy and provides an opportunity to improve wheat's genetic diversity through alien gene introgression, a major bottleneck facing crop improvement.

• MeSH
• alely MeSH
• chiméra MeSH
• chromozomy rostlin chemie   MeSH
• DNA rostlinná genetika   metabolismus   MeSH
• fyzikální mapování chromozomů MeSH
• homologní rekombinace * MeSH
• meióza MeSH
• mutace MeSH
• oprava chybného párování bází DNA MeSH
• ploidie MeSH
• pšenice genetika   metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• šlechtění rostlin metody   MeSH
• žito genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The present study aimed to investigate and compare fitness-related traits and ploidy levels of purebreds and hybrids produced from sturgeon broodstock with both normal and abnormal ploidy levels. We used diploid Acipenser ruthenus and tetraploid A. baerii males and females to produce purebreds and reciprocal hybrids of normal ploidy levels. Likewise, we used diploid A. ruthenus and tetraploid A. baerii females mated to pentaploid and hexaploid A. baerii males to produce hybrids of abnormal ploidy levels. Fertilization of ova of A. ruthenus and A. baerii of normal ploidy with the sperm of pentaploid and hexaploid A. baerii produced fully viable progeny with ploidy levels that were intermediate between those of the parents as was also found in crosses of purebreds and reciprocal hybrids of normal ploidy levels. The A. ruthenus × pentaploid A. baerii and A. ruthenus × hexaploid A. baerii hybrids did not survive after 22 days post-hatch (dph). Mean body weight and cumulative survival were periodically checked at seven-time intervals. The recorded values of mean body weight were significantly higher in A. baerii × pentaploid A. baerii hybrids than other groups at three sampling points (160, 252 and 330 dph). In contrast, the highest cumulative survival was observed in A. baerii × A. ruthenus hybrids at all sampling points (14.47 ± 5.70 at 497 dph). Overall, most of the studied sturgeon hybrids displayed higher mean BW and cumulative survival compared to the purebreds. The utilization of sturgeon hybrids should be restricted to aquaculture purposes because they can pose a significant genetic threat to native populations through ecological interactions.

• MeSH
• chiméra genetika   růst a vývoj   MeSH
• chromozomy MeSH
• genom MeSH
• molekulární evoluce * MeSH
• oocyty cytologie   fyziologie   MeSH
• ploidie * MeSH
• ryby genetika   růst a vývoj   MeSH
• spermie cytologie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Parasites of the genus Leishmania (Kinetoplastida: Trypanosomatidae) cause widespread and devastating human diseases. Visceral leishmaniasis due to Leishmania donovani is endemic in Ethiopia where it has also been responsible for major epidemics. The presence of hybrid genotypes has been widely reported in surveys of natural populations, genetic variation reported in a number of Leishmania species, and the extant capacity for genetic exchange demonstrated in laboratory experiments. However, patterns of recombination and the evolutionary history of admixture that produced these hybrid populations remain unclear. Here, we use whole-genome sequence data to investigate Ethiopian L. donovani isolates previously characterized as hybrids by microsatellite and multi-locus sequencing. To date there is only one previous study on a natural population of Leishmania hybrids based on whole-genome sequences. We propose that these hybrids originate from recombination between two different lineages of Ethiopian L. donovani occurring in the same region. Patterns of inheritance are more complex than previously reported with multiple, apparently independent, origins from similar parents that include backcrossing with parental types. Analysis indicates that hybrids are representative of at least three different histories. Furthermore, isolates were highly polysomic at the level of chromosomes with differences between parasites recovered from a recrudescent infection from a previously treated individual. The results demonstrate that recombination is a significant feature of natural populations and contributes to the growing body of data that shows how recombination, and gene flow, shape natural populations of Leishmania.

• MeSH
• chiméra * MeSH
• genotyp MeSH
• Leishmania donovani genetika   MeSH
• leishmanióza viscerální parazitologie   MeSH
• lidé MeSH
• rekombinace genetická MeSH
• sekvenování celého genomu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Etiopie MeSH

Chromosome pairing in meiosis usually starts in the vicinity of the telomere attachment to the nuclear membrane and congregation of telomeres in the leptotene bouquet is believed responsible for bringing homologue pairs together. In a heterozygote for an inversion of a rye (Secale cereale L.) chromosome arm in wheat, a distal segment of the normal homologue is capable of chiasmate pairing with its counterpart in the inverted arm, located near the centromere. Using 3D imaging confocal microscopy, we observed that some telomeres failed to be incorporated into the bouquet and occupied various positions throughout the entire volume of the nucleus, including the centromere pole. Rye telomeres appeared ca. 21 times more likely to fail to be included in the telomere bouquet than wheat telomeres. The frequency of the out-of-bouquet rye telomere position in leptotene was virtually identical to the frequency of telomeres deviating from Rabl's orientation in the nuclei of somatic cells, and was similar to the frequency of synapsis of the normal and inverted chromosome arms, but lower than the MI pairing frequency of segments of these two arms normally positioned across the volume of the nucleus. Out-of-position placement of the rye telomeres may be responsible for reduced MI pairing of rye chromosomes in hybrids with wheat and their disproportionate contribution to aneuploidy, but appears responsible for initiating chiasmate pairing of distantly positioned segments of homology in an inversion heterozygote.

• MeSH
• buněčné jádro genetika   ultrastruktura   MeSH
• centromera chemie   ultrastruktura   MeSH
• chiméra genetika   MeSH
• chromozomální inverze * MeSH
• chromozomy rostlin chemie   ultrastruktura   MeSH
• druhová specificita MeSH
• heterozygot MeSH
• hybridizace in situ fluorescenční MeSH
• konfokální mikroskopie MeSH
• párování chromozomů MeSH
• počítačové zpracování obrazu statistika a číselné údaje   MeSH
• profáze meiózy I * MeSH
• pšenice genetika   ultrastruktura   MeSH
• rostlinné buňky metabolismus   ultrastruktura   MeSH
• telomery chemie   ultrastruktura   MeSH
• žito genetika   ultrastruktura   MeSH
• zobrazování trojrozměrné metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Successful derivation and cultivation of primordial germ cells (PGCs) opened the way to efficient transgenesis and genome editing in the chicken. Furthermore, implantation of male PGCs from non-chicken galliform species into the chicken embryos resulted in cross-species germline chimeras and viable offspring. We have recently improved the PGC technology by demonstrating that chicken male PGCs transplanted into the testes of adult cockerel recipients mature into functional sperms. However, the availability of this orthotopic transplantation for cross-species transfer remains to be explored. Here we tested the capacity of genetically distant male PGCs to mature in the microenvironment of adult testes. We derived PGCs from the Chinese black-bone Silkie and transplanted them into infertile White Leghorn cockerels. Within 15-18 weeks after transplantation, we observed restoration of spermatogenesis in recipient cockerels and production of healthy progeny derived from the transplanted PGCs. Our findings also indicate the possibility of cross-species orthotopic transplantation of PGCs. Thus, our results might contribute to the preservation of endangered avian species and maintaining the genetic variability of the domestic chicken.

• MeSH
• chiméra genetika   MeSH
• chov metody   MeSH
• křížení genetické MeSH
• kultivované buňky MeSH
• kur domácí * klasifikace   genetika   MeSH
• kuřecí embryo MeSH
• ohrožené druhy MeSH
• spermatogeneze fyziologie   MeSH
• spermie cytologie   transplantace   MeSH
• testis cytologie   MeSH
• transplantace heterologní veterinární   MeSH
• zachování plodnosti metody   veterinární   MeSH
• zachování přírodních zdrojů * metody   MeSH
• zárodečné buňky transplantace   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In perennial plants, seasonal shifts provide cues that control adaptive growth patterns of the shoot apex. However, where these seasonal cues are sensed and communicated to the shoot apex remains unknown. We demonstrate that systemic signals from leaves play key roles in seasonal control of shoot growth in model tree hybrid aspen. Grafting experiments reveal that the tree ortholog of Arabidopsis flowering time regulator FLOWERING LOCUS T (FT) and the plant hormone gibberellic acid (GA) systemically convey seasonal cues to the shoot apex. GA (unlike FT) also acts locally in shoot apex, downstream of FT in seasonal growth control. At the shoot apex, antagonistic factors-LAP1, a target of FT and the FT antagonist TERMINAL FLOWER 1 (TFL1)-act locally to promote and suppress seasonal growth, respectively. These data reveal seasonal changes perceived in leaves that are communicated to the shoot apex by systemic signals that, in concert with locally acting components, control adaptive growth patterns.

• MeSH
• Arabidopsis fyziologie   MeSH
• chiméra růst a vývoj   MeSH
• fotoperioda MeSH
• fyziologie rostlin MeSH
• gibereliny metabolismus   MeSH
• proteiny huseníčku metabolismus   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• roční období MeSH
• signální transdukce fyziologie   MeSH
• výhonky rostlin růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cell chimerism determination is important for the monitoring of engraftment dynamics and for relapse prediction. Our cohort of 474 patients was divided into two groups according to the determination methods used over time, and by their chimerism status. A significant difference in survival was observed between mixed vs complete chimerism (P < 0.0001 vs P < 0.0002) in both patient groups, and also vs microchimerism (P = 0.0201) in the second group. Detection of mixed chimerism is thus a high-risk factor, and microchimerism is potentially a risk factor in the post-transplantation course. Methods with a high sensitivity for monitoring cell chimerism significantly improve the assessment of patients post-transplant, and they enable the identification of patients with high relapse risk. Supported by MH CZ-DRO (00023736, UHKT).

• MeSH
• analýza přežití MeSH
• dospělí MeSH
• genetické testování metody   MeSH
• hematologické nádory genetika   imunologie   mortalita   terapie   MeSH
• homologní transplantace MeSH
• imunologická tolerance * MeSH
• kohortové studie MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• myeloablativní agonisté terapeutické užití   MeSH
• nemoc štěpu proti hostiteli diagnóza   genetika   imunologie   mortalita   MeSH
• přežívání štěpu * MeSH
• příprava pacienta k transplantaci metody   MeSH
• recidiva MeSH
• rejekce štěpu diagnóza   genetika   imunologie   mortalita   MeSH
• rizikové faktory MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• tandemové repetitivní sekvence MeSH
• testování histokompatibility MeSH
• transplantace hematopoetických kmenových buněk * MeSH
• transplantační chiméra genetika   imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The increase of mixed chimerism (MC) after allogeneic hematopoietic stem cell transplantation has been associated with a high risk of relapse. A variety of techniques that use polymorphic markers have been established to survey hematopoietic chimerism status. The highest sensitivity is achieved using real-time quantitative polymerase chain reaction (RQ-PCR) analysis of insertion/deletion polymorphism, which allows the detection of disease recurrence and subsequently the earlier initiation of therapeutic intervention. The purpose of this study is the evaluation of multiplex RQ-PCR for MC assessment (six biallelic genetic systems and Y-specific locus), allowing the amplification and detection of target gene of interest and glyceraldehyde-3-phosphate dehydrogenase reference housekeeping gene in a single microtube. With optimized amounts of primers and probe, the quantification of target DNA was shown to be linear throughout the tested range (100%-0.05%). The efficiencies of multiplex RQ-PCR were in a range of 0.89 to 1.07. The sensitivity of individual systems ranged 0.02% to 0.04% with an average of 0.034%. A high degree of linear correlation between the chimerism results obtained by multiplex RQ-PCR vs singleplex RQ-PCR was observed (P < 0.0001, Spearman's coefficient = 0.9927), while correlation between multiplex RQ-PCR vs short tandem repeat analysis was also statistically significant (P < 0.0001, Spearman's coefficient = 0.9769). This new multiplex RQ-PCR assay is a quick, sensitive, reproducible, and cost-effective method for accurate MC assessment.

• MeSH
• alely MeSH
• chimérismus * MeSH
• DNA primery MeSH
• leukemie terapie   MeSH
• lidé MeSH
• lokální recidiva nádoru diagnóza   etiologie   prevence a kontrola   MeSH
• multiplexová polymerázová řetězová reakce metody   MeSH
• polymerázová řetězová reakce s reverzní transkripcí metody   MeSH
• polymorfismus genetický * MeSH
• transplantace hematopoetických kmenových buněk škodlivé účinky   MeSH
• transplantační chiméra krev   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromosomal rearrangements (e.g., fusions/fissions) have the potential to drive speciation. However, their accumulation in a population is generally viewed as unlikely, because chromosomal heterozygosity should lead to meiotic problems and aneuploid gametes. Canonical meiosis involves segregation of homologous chromosomes in meiosis I and sister chromatid segregation during meiosis II. In organisms with holocentric chromosomes, which are characterized by kinetic activity distributed along almost the entire chromosome length, this order may be inverted depending on their metaphase I orientation. Here we analyzed the evolutionary role of this intrinsic versatility of holocentric chromosomes, which is not available to monocentric ones, by studying F1 to F4 hybrids between two chromosomal races of the Wood White butterfly (Leptidea sinapis), separated by at least 24 chromosomal fusions/fissions. We found that these chromosomal rearrangements resulted in multiple meiotic multivalents, and, contrary to the theoretical prediction, the hybrids displayed relatively high reproductive fitness (42% of that of the control lines) and regular behavior of meiotic chromosomes. In the hybrids, we also discovered inverted meiosis, in which the first and critical stage of chromosome number reduction was replaced by the less risky stage of sister chromatid separation. We hypothesize that the ability to invert the order of the main meiotic events facilitates proper chromosome segregation and hence rescues fertility and viability in chromosomal hybrids, potentially promoting dynamic karyotype evolution and chromosomal speciation.

• MeSH
• chiméra * genetika   metabolismus   MeSH
• chromatidy * genetika   metabolismus   MeSH
• chromozomy hmyzu genetika   metabolismus   MeSH
• metafáze fyziologie   MeSH
• motýli * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Transgenic mice expressing green fluorescent protein (GFP) are useful in transplantation experiments. When we used ubiquitin-GFP (UBC-GFP) transgenic mice to study the availability of niches for transplanted hematopoietic stem and progenitor cells, the results were strikingly different from the corresponding experiments that used congenic mice polymorphic in the CD45 antigen. Analysis of these unexpected results revealed that the hematopoiesis of UBC-GFP mice was outcompeted by the hematopoiesis of wild-type (WT) mice. Importantly, UBC-GFP mice engrafted the transplanted bone marrow of WT mice without conditioning. There was a significant bias toward lymphopoiesis in the WT branch of chimeric UBC-GFP/WT hematopoiesis. A fraction of immature Sca-1+ cells in the spleen of UBC-GFP mice expressed GFP at a very high level. The chimeric hematopoiesis was stable in the long term and also after transplantation to secondary recipient mice. The article thus identifies a specific defect in the hematopoiesis of UBC-GFP transgenic mice that compromises the lymphoid-primed hematopoietic stem cells in the bone marrow and spleen. Stem Cells 2018;36:1237-1248.

• MeSH
• chiméra MeSH
• hematopoetické kmenové buňky metabolismus   MeSH
• hematopoéza MeSH
• kostní dřeň metabolismus   MeSH
• lymfocyty metabolismus   MeSH
• lymfopoéza MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• slezina metabolismus   MeSH
• splenektomie MeSH
• thymus metabolismus   MeSH
• transplantace hematopoetických kmenových buněk * MeSH
• ubikvitin metabolismus   MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH