Výsledky v zjištěných hodnotách disjunktivních reakčně-rychlostních schopností dolních končetin poukazují na stejnou genetickou výbavu jednovaječných dvojčat a rozdílnost mezi nimi a dvojčaty dvouvaječnými. Agility test se jeví jako vhodný pro sporty, kde reakčně-rychlostní schopnosti limitují sportovní výkon.

Results in observed values of lower limbs disjunctive reaction-speed abilities suggest similar genetic endowment of identical twins and diferences between biovular twins. We recommend the agility test as a suitable tool for sports where the reaction-speed abilities limit sports performance.

• Klíčová slova
• monozygotická a dizygotická dvojčata, lateralita, disjunktivní reakčně-rychlostní schopnosti,
• MeSH
• dolní končetina MeSH
• dospělí MeSH
• dvojčata MeSH
• funkční lateralita genetika   MeSH
• lidé MeSH
• psychomotorický výkon klasifikace   MeSH
• sportovci MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH

Understanding transcontinental biogeographic patterns has been one of the main foci of the field of biogeography. While multiple explanations for transcontinental disjunctions have been proposed, little is still known about the relative importance of intrinsic and extrinsic traits for the diversification dynamics of disjunct taxa. Here, we study the evolutionary history of the genus Picris L. (Compositae), a great model for investigating the diversification dynamics of transoceanic bipolar disjunct organisms. Ancestral state reconstructions indicate that the most recent common ancestor (MRCA) of Picris was a semelparous and heterocarpic herb that lived in unpredictable environments of North Africa and West Asia. Diversification analyses suggest a significant shift in speciation ca. 1 million years ago, likely associated with the onset of the mid-Pleistocene revolution. Longevity characters are correlated with the evolution of particular fruit types and with environmental conditions. Heterocarpic species are mostly semelparous herbs strongly linked with unpredictable habitats, while homocarpic taxa are mostly iteroparous plants occurring in predictable environments. Binary-state speciation and extinction analyses suggest that homocarpy, iteroparity, and habitats predictability accelerate diversification. Although the combination of homocarpy and iteroparity evolved in several lineages, only members of the P. hieracioides group were able to colonise Eurasia and expand to Australia by transoceanic dispersal. Those findings indicate that large-scale colonisation events depend on a complex interplay of intrinsic and extrinsic factors.

• MeSH
• Asteraceae klasifikace   MeSH
• Bayesova věta MeSH
• biodiverzita * MeSH
• biologické modely MeSH
• fenotyp MeSH
• fylogeneze MeSH
• fylogeografie MeSH
• kvantitativní znak dědičný MeSH
• podnebí * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Asie MeSH
• Austrálie MeSH
• severní Afrika MeSH

• MeSH
• nondisjunkce genetická MeSH
• struktury chromozomu ultrastruktura   MeSH

• MeSH
• epitel anatomie a histologie   embryologie   MeSH
• lidé MeSH
• morfogeneze MeSH
• oční víčka anatomie a histologie   embryologie   MeSH
• Check Tag
• lidé MeSH

Causes of chromosomal nondisjunction is one of the remaining unanswered questions in human genetics. In order to increase our understanding of the mechanisms underlying nondisjunction we have performed a molecular study on trisomy 8 and trisomy 8 mosaicism. We report the results on analyses of 26 probands (and parents) using 19 microsatellite DNA markers mapping along the length of chromosome 8. The 26 cases represented 20 live births, four spontaneous abortions, and two prenatal diagnoses (CVS). The results of the nondisjunction studies show that 20 cases (13 maternal, 7 paternal) were probably due to mitotic (postzygotic) duplication as reduction to homozygosity of all informative markers was observed and as no third allele was ever detected. Only two cases from spontaneous abortions were due to maternal meiotic nondisjunction. In four cases we were not able to detect the extra chromosome due to a low level of mosaicism. These results are in contrast to the common autosomal trisomies (including mosaics), where the majority of cases are due to errors in maternal meiosis.

• MeSH
• dítě MeSH
• genomový imprinting MeSH
• kojenec MeSH
• lidé MeSH
• lidské chromozomy, pár 8 * MeSH
• mozaicismus * MeSH
• nondisjunkce genetická * MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• trizomie * MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH

The genomes of many plants, animals, and fungi frequently comprise dispensable B chromosomes that rely upon various chromosomal drive mechanisms to counteract the tendency of non-essential genetic elements to be purged over time. The B chromosome of rye - a model system for nearly a century - undergoes targeted nondisjunction during first pollen mitosis, favouring segregation into the generative nucleus, thus increasing their numbers over generations. However, the genetic mechanisms underlying this process are poorly understood. Here, using a newly-assembled, ~430 Mb-long rye B chromosome pseudomolecule, we identify five candidate genes whose role as trans-acting moderators of the chromosomal drive is supported by karyotyping, chromosome drive analysis and comparative RNA-seq. Among them, we identify DCR28, coding a microtubule-associated protein related to cell division, and detect this gene also in the B chromosome of Aegilops speltoides. The DCR28 gene family is neo-functionalised and serially-duplicated with 15 B chromosome-located copies that are uniquely highly expressed in the first pollen mitosis of rye.

• MeSH
• Aegilops genetika   metabolismus   MeSH
• chromozomy rostlin * genetika   MeSH
• karyotypizace MeSH
• mitóza * genetika   MeSH
• nondisjunkce genetická MeSH
• pyl genetika   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné geny MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• žito * genetika   MeSH
• Publikační typ
• časopisecké články MeSH

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermesat 59.5 Ma (49.9-69.5 Ma 95% CI), yet the oldest split within Reticulitermes(Eurasia and North America) is 16.1 Ma (13.4-19.5 Ma) and the oldest split within Heterotermes + Coptotermesis 36.0 Ma (33.9-40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives.

• MeSH
• druhová specificita MeSH
• fylogeneze MeSH
• genom hmyzu * MeSH
• genom mitochondriální * MeSH
• Isoptera genetika   fyziologie   MeSH
• rozšíření zvířat * MeSH
• sekvenční analýza DNA MeSH
• sekvenční seřazení MeSH
• zavlečené druhy MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• Downův syndrom epidemiologie   genetika   MeSH
• finanční podpora výzkumu jako téma MeSH
• genomový imprinting MeSH
• lidé MeSH
• meióza MeSH
• nondisjunkce genetická MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Geografické názvy
• Rusko MeSH
• Ukrajina MeSH

B chromosomes (Bs) are supernumerary chromosomes, which are often preferentially inherited. When transmission rates of chromosomes are higher than 0.5, not obeying the Mendelian law of equal segregation, the resulting transmission advantage is collectively referred to as 'chromosome drive'. Here we analysed the drive mechanism of Aegilops speltoides Bs. The repeat AesTR-183 of A. speltoides Bs, which also can be detected on the Bs of Aegilops mutica and rye, was used to track Bs during pollen development. Nondisjunction of CENH3-positive, tubulin interacting B sister chromatids and an asymmetric spindle during first pollen grain mitosis are key for the accumulation process. A quantitative flow cytometric approach revealed that, independent of the number of Bs present in the mother plant, Bs accumulate in the generative nuclei to > 93%. Nine out of 11 tested (peri)centromeric repeats were shared by A and B chromosomes. Our findings provide new insights into the process of chromosome drive. Quantitative flow cytometry is a useful and reliable method to study the drive frequency of Bs. Nondisjunction and unequal spindle organization accompany during first pollen mitosis the drive of A. speltoides Bs. The prerequisites for the drive process seems to be common in Poaceae.

• MeSH
• Aegilops genetika   MeSH
• aparát dělícího vřeténka metabolismus   MeSH
• buněčné jádro genetika   MeSH
• centromera metabolismus   MeSH
• chromozomy rostlin genetika   MeSH
• konzervovaná sekvence genetika   MeSH
• mitóza genetika   MeSH
• nondisjunkce genetická * MeSH
• pyl genetika   MeSH
• repetitivní sekvence nukleových kyselin genetika   MeSH
• sekvence nukleotidů MeSH
• žito genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Chromosome segregation in mammalian oocytes is prone to errors causing aneuploidy with consequences such as precocious termination of development or severe developmental disorders. Aneuploidy also represents a serious problem in procedures utilizing mammalian gametes and early embryos in vitro. In our study, we focused on congression defects during meiosis I and observed whole nondisjoined bivalents in meiosis II as a direct consequence, together with a substantially delayed first polar body extrusion. We also show that the congression defects are accompanied by less stable attachments of the kinetochores. Our results describe a process by which congression defects directly contribute to aneuploidy.

• MeSH
• aneuploidie * MeSH
• časosběrné zobrazování metody   MeSH
• kinetochory metabolismus   MeSH
• konfokální mikroskopie MeSH
• meióza genetika   MeSH
• mikrotubuly metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nondisjunkce genetická * MeSH
• oocyty metabolismus   MeSH
• segregace chromozomů genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH