Transmission of mitochondrial DNA following assisted reproduction and nuclear transfer

Review of the articleMitochondria are the organelles responsible for producing the majority of a cell's ATP and also play an essential role in gamete maturation and embryo development. ATP production within the mitochondria is dependent on proteins encoded by both the nuclear and the mitochondrial genomes, therefore co-ordination between the two genomes is vital for cell survival. To assist with this co-ordination, cells normally contain only one type of mitochondrial DNA (mtDNA) termed homoplasmy. Occasionally, however, two or more types of mtDNA are present termed heteroplasmy. This can result from a combination of mutant and wild-type mtDNA molecules or from a combination of wild-type mtDNA variants. As heteroplasmy can result in mitochondrial disease, various mechanisms exist in the natural fertilization process to ensure the maternal-only transmission of mtDNA and the maintenance of homoplasmy in future generations. However, there is now an increasing use of invasive oocyte reconstruction protocols, which tend to bypass mechanisms for the maintenance of homoplasmy, potentially resulting in the transmission of either form of mtDNA heteroplasmy. Indeed, heteroplasmy caused by combinations of wild-type variants has been reported following cytoplasmic transfer (CT) in the human and following nuclear transfer (NT) in various animal species. Other techniques, such as germinal vesicle transfer and pronuclei transfer, have been proposed as methods of preventing transmission of mitochondrial diseases to future generations. However, resulting embryos and offspring may contain mtDNA heteroplasmy, which itself could result in mitochondrial disease. It is therefore essential that uniparental transmission of mtDNA is ensured before these techniques are used therapeutically

Seeing red? The Effect of Colour on Intelligence Test Performance

A series of recent studies reported that seeing red was associated with poor intelligence test performance in university students. Here we test for the first time the effect of colour on intelligence test scores in an adult sample and across a large battery of ability tests. Overall 200 British adults completed Raven’s matrices without colour manipulation (i.e. baseline assessment); afterwards, they then either viewed red or green before completing six additional ability tests (i.e. word fluency, logical reasoning, vocabulary, syllogisms, verbal reasoning, and knowledge) and rating their self-perceived performance for each measure. We found no evidence for an association between colour and intelligence test scores or self-perceived performance, before and after adjusting for intelligence at baseline. The discrepancy with previous findings is likely to be due to testing adult rather than student samples, which in turn has implications for the recruitment and selection of study samples in future intelligence research

Seeing red? The Effect of Colour on Intelligence Test Performance

A series of recent studies reported that seeing red was associated with poor intelligence test performance in university students. Here we test for the first time the effect of colour on intelligence test scores in an adult sample and across a large battery of ability tests. Overall 200 British adults completed Raven’s matrices without colour manipulation (i.e. baseline assessment); afterwards, they then either viewed red or green before completing six additional ability tests (i.e. word fluency, logical reasoning, vocabulary, syllogisms, verbal reasoning, and knowledge) and rating their self-perceived performance for each measure. We found no evidence for an association between colour and intelligence test scores or self-perceived performance, before and after adjusting for intelligence at baseline. The discrepancy with previous findings is likely to be due to testing adult rather than student samples, which in turn has implications for the recruitment and selection of study samples in future intelligence research

Internal representations of smell in the Drosophila brain

Recent advances in sensory neuroscience using Drosophila olfaction as a model system have revealed brain maps representing the external world. Once we understand how the brain's built-in capability generates the internal olfactory maps, we can then elaborate how the brain computes and makes decision to elicit complex behaviors. Here, we review current progress in mapping Drosophila olfactory circuits and discuss their relationships with innate olfactory behaviors

DEVELOPMENT of the MODEL of GALACTIC INTERSTELLAR EMISSION for STANDARD POINT-SOURCE ANALYSIS of FERMI LARGE AREA TELESCOPE DATA

Most of the celestial \u3b3 rays detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point-source and extended-source studies rely on the modeling of this diffuse emission for accurate characterization. Here, we describe the development of the Galactic Interstellar Emission Model (GIEM), which is the standard adopted by the LAT Collaboration and is publicly available. This model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission produced in the Galaxy. In the GIEM, we also include large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20\ub0 and we observe an enhanced emission toward their base extending in the north and south Galactic directions and located within \u2dc4\ub0 of the Galactic Center