From genetics to epigenetics

Genetic Variation in Schizothorax kozlovi Nikolsky in the Upper Reaches of the Chinese Yangtze River Based on Genotyping for Simplified Genome Sequencing

Simple Summary

Schizothorax kozlovi Nikolsky is a unique cold−water fish in the upper reaches of the Yangtze River in China and has high economic value. In our study, genetic diversity and population structure analyses were performed on seven wild populations in the upper reaches of the Yangtze River by GBS. The above results indicate that the populations of S. kozlovi have different degrees of tolerance and selection pressure in response to temperature and altitude. The Wujiang population was genetically differentiated from the Jinsha River and Yalong River populations. The Wujiang intrapopulation has greater genetic diversity and differentiation than the Jinsha River and Yalong River populations, which demonstrates that the Jinsha and Yalong populations require more attention and resources for their protection. The results of this study will increase our understanding of the diversity of S. kozlovi in the upper reaches of the Yangtze River and provide a basis for the conservation and utilization of wild resources.

Abstract

Schizothorax kozlovi Nikolsky is a unique cold−water fish in the upper reaches of the Yangtze River in China and has high economic value. In our study, genetic diversity and population structure analyses were performed on seven wild populations (originating from the Jinsha River, Yalong River, and Wujiang River) in the upper reaches of the Yangtze River by genotyping by sequencing (GBS). The results indicated that a total of 303,970 single−nucleotide polymorphisms (SNPs) were identified from the seven wild populations. Lower genetic diversity was exhibited among the intrapopulations of the three tributaries, and the Wujiang River population had significant genetic differentiation when compared to the Jinsha River and Yalong River populations. Furthermore, the selected SNPs were enriched in cellular processes, environmental adaptation, signal transduction, and related metabolic processes between the Wujiang population and the other two populations. The above results indicate that the populations of S. kozlovi have different degrees of tolerance and selection pressure in response to temperature and altitude. The Wujiang intrapopulation has greater genetic diversity and differentiation than the Jinsha River and Yalong River populations, which demonstrates that the Jinsha and Yalong populations require more attention and resources for their protection. The results of this study will increase our understanding of the diversity of S. kozlovi in the upper reaches of the Yangtze River and provide a basis for the conservation and utilization of wild resources.

Epigenetic Modification of PD-1/PD-L1-Mediated Cancer Immunotherapy against Melanoma

Malignant melanoma is one of the representative skin cancers with unfavorable clinical behavior. Immunotherapy is currently used for the treatment, and it dramatically improves clinical outcomes in patients with advanced malignant melanoma. On the other hand, not all these patients can obtain therapeutic efficacy. To overcome this limitation of current immunotherapy, epigenetic modification is a highlighted issue for clinicians. Epigenetic modification is involved in various physiological and pathological conditions in the skin. Recent studies identified that skin cancer, especially malignant melanoma, has advantages in tumor development, indicating that epigenetic manipulation for regulation of gene expression in the tumor can be expected to result in additional therapeutic efficacy during immunotherapy. In this review, we focus on the detailed molecular mechanism of epigenetic modification in immunotherapy, especially anti-PD-1/PD-L1 antibody treatment for malignant melanoma.

Hyperphenylalaninaemias in Estonia: Genotype-Phenotype Correlation and Comparative Overview of the Patient Cohort Before and After Nation-Wide Neonatal Screening

The present study provides a retrospective overview of the cohort of phenylketonuria (PKU) patients in Estonia. Based on the available data, the patients clearly cluster into two distinct groups: the patients with late diagnosis and start of therapy (N = 46), who were born before 1993 when the national newborn screening programme was launched, and the screened babies (N = 48) getting their diagnoses at least in a couple of weeks after birth.Altogether 153 independent phenylalanine hydroxylase (PAH) alleles from 92 patients were analysed in the study, wherein 80% of them were carrying the p.Arg408Trp variation, making the relative frequency of this particular variation one of the highest known. Additionally, 15 other different variations in the PAH gene were identified, each with very low incidence, providing ground for phenotypic variability and potential response to BH₄ therapy. Genealogical analysis revealed some "hotspots" of the origin of the p.Arg408Trp variation, with especially high density in South-East Estonia. According to our data, the incidence of PKU in Estonia is estimated as 1 in 6,700 newborns.

What is a psychosis and where is it located?

Kraepelin's dichotomy, manic-depressive insanity and dementia praecox, are contrasting and true endogenous disease entities which affect excitability, the fundamental property of the CNS. Kraepelin wanted to establish a valid classification and hit the extremes in brain structure and function at a time when we had no knowledge of brain dysfunction in "functional" psychoses. The aetiology is now known: the psychoses are part of human growth and maturation and might be classified according to their brain dysfunction, which is exactly what Kraepelin wanted. However, presumably to reduce the stigma attached to the word "psychosis", there is currently a strong initiative to eliminate the concept. But knowledge of what is happening in the brain in a psychosis might be more helpful in reducing stigma. It is suggested that psychosis is due to an affection of the supplementary motor area (SMA), located at the centre of the Medial Frontal Lobe network. The SMA is one of the rare universally connected areas of the brain, as should be the case for such a key structure that makes decisions as to the right moment for action. This important network, which partly has continuous neurogenesis, has sufficiently widespread connections. The SMA, a premotor area located on the medial side of the frontal lobes, is one of the last regions to reach a concurrence of synaptogenesis. An affection of the SMA, a deficient or abolished Delayed Response Task, seriously disturbs our relation and adaptation to the surroundings. We usually master the Delayed Response Task around the age of 7 months, a time at which the second CNS regressive event takes place, which proceeds from the posterior to the anterior of the brain. In very late maturation, a persistent affection of the SMA might occur. We experience a chronic psychosis: infantile autism (IA), a chronic inability to act consciously, which contrasts with the episodic SMA affection post-puberty, when excitation is reduced due to excessive pruning of excitatory synapses. Silent spots are the result of insufficient fill-in mechanisms following a breakdown of circuitry. They may affect the SMA in the case of very late puberty. An acute reduction in excitation and concomitantly a marked increase in silent spots might lead to an acute psychosis. A frontal preference is likely, given that a reduction might occur anywhere in the cortex, but particularly in the areas maturing latest. The varying localisations probably explain the difficulty in accepting schizophrenia as a disease entity. The multifactorial inheritance of the dichotomy implies that the genetics are not fate, a psychotic development might be prevented given enough epigenetic factors: brain food (omega 3). Might the present dietary adversity, with its lack of brain food, be responsible for a rising incidence in psychosis? A psychosis is an understandable and preventable dysfunction of the brain, and its mechanisms are known. Primarily a disorder of reduced excitation in an attenuated CNS, this explains why all the neuroleptics are convulsants, raising excitation, in contrast to all antidepressives, which are anti-epileptic.