Genética humana y embriología

Reprogenetics is a subset of preimplantation genetic diagnosis, which is a well-established medical practise (PGD). PGD (prenatal diagnosis, or testing of foetal tissue for the presence of disease genes) allows couples at risk of transmitting a genetic disease to ensure that their future children are unaffected by the disease without having to go through the difficult process of prenatal diagnosis (i.e., testing of foetal tissue for the presence of disease genes) and having to make the difficult decision of terminating the pregnancy. PGD is taking a single cell from an eight-cell embryo (produced through in vitro fertilisation) and testing its DNA for the presence of one or more disease-associated genetic changes. The mother's uterus is then only implanted with embryos that do not have the illness mutation. PGD was originally utilised in clinical treatment in the early 1990s to determine the sex of embryos in order to reduce the risk of passing on fatal sex-linked illness genes to offspring. If there is a family history of Duchenne muscular dystrophy (DMD), for example, parents may choose to have their embryos screened to distinguish between female and male embryos before implanting solely the female embryos.

Double aneuploidy is prevalent, especially in conceived products, and is commonly caused by the combination of a sex chromosome and an acrocentric chromosome. Only five examples of double autosomal trisomy have been recorded. Only three occurrences of double aneuploidy mosaicism involving two separate cell lines have been recorded. A fourth occurrence of double aneuploidy mosaicism on a newborn is reported. A preliminary 24-hour chromosomal study at delivery revealed a mosaic karyotype, 47,XX,+18[15]/47,XX,+21[8]/48,XX,+21,+mar[7]. Reflex testing to SNP microarray with the same material obtained at birth revealed chromosome 18 increase of 77.9 Mb and chromosomal 21 gain of 32.5 Mb. The microarray revealed no further copy number alterations, implying that the marker chromosome does not contain any euchromatic material. At one year of life, a repeat chromosome analysis revealed a mosaic karyotype, 47,XX,+18[76]/47,XX,+21[4], with loss of the marker cell line. Double aneuploidy is prevalent, particularly in conceived products, and typically involves a sex chromosome and an acrocentric chromosome. 

It has long been an aim to attain desired mechanical characteristics in alloys by controlling phase formation, particularly in intricate multi-phase alloys. In fact, the composition of the liquid influences the nucleation of competing crystalline phases during solidification. We use ab initio molecular dynamics simulations (AIMD) to disclose the liquid structure of Mg-Al-Ca alloys and investigate its influence on the change of Ca-containing Laves phase from Al2Ca to Mg2Ca when the Ca/Al ratio (rCa/Al) increases. In terms of the local arranging environment and polyhedra connection schemes, there is structural similarity between the liquid and crystalline phases. As shown by the topological and chemical short-range order arising from liquid, the forming signature of Mg2Ca ascends monotonically with increasing rCa/Al. However, at the crossover of rCa/Al = 0.74, the Al2Ca crystal-like order increases at first and subsequently decreases, according to the observed composition of the phase transition from Al2Ca to Mg2Ca. The tight packing of atomic configurations and preferential bonding of chemical species in both liquid and solid are the origins of phase change across various compositions.

Genetic diseases are becoming more widely recognised in paediatrics. Close to 10% of diseases in hospitalised children have been linked to Mendelian traits inherited as single gene defects, which is not surprising given that approximately 1000 inborn errors of metabolism (IEM) have been discovered to date, primarily through the detection of abnormally accumulated endogenous metabolites in biological fluids and tissues. Clinical biochemical genetics is a laboratory discipline that deals with the evaluation and diagnosis of patients and families with inherited metabolic disease, as well as the monitoring of treatment and the differentiation of heterozygous carriers from non-carriers using metabolite and enzymic analysis of physiological fluids and tissues. The biochemical genetics lab is not the same as the clinical chemistry lab.

Parasitism is an extremely effective life strategy and a driving factor in genetic diversity that has developed several times. Infections of unintended hosts provide a chance for lateral host changes and parasite niche expansion. However, if directed toward creatures that are phylogenetically far from the parasite's native host, such as humans, it may create a deadend environment in which the parasite fails to grow or is destroyed by host immunity. One example is worms of the Anisakidae family, genus Anisakis, which have lost the capacity to replicate in terrestrial hosts but may live in humans for a brief period, producing anisakiasis. To investigate Anisakis' ability to infect an evolutionary distant host, we performed transcriptome profiling on larvae successfully migrating through the rat, a classic model of accidental human infection, and compared it to that of larvae infecting an evolutionary familiar, paratenic host (fish).