[Transgenerational epigenetics and its bioethical implications]. / La epigenética transgeneracional y sus implicaciones bioéticas.

Epigenetics deals with the study of modifications that affect gene expression without altering the base composition of DNA. It can take place in a programmed way, such as the one that determines the different cellular specialties and tissues that arise during embryonic development, or it can occur randomly due to the influence of uncontrolled environmental factors, with possible consequences for health. The different epigenetic mechanisms that determine the states of activity or silencing of genes and their biological role in the regulation of gene expression, especially in higher animals, are presented. In general, epigenetic modifications are erased during early embryogenesis, so they are not transmitted from generation to generation, but their incidence during embryogenesis may be the cause of the appearance of effects that can affect health after birth, the F1 , or its offspring, F2 (intergenerational inheritance). At least in animals, transgenerational inheritance (more than two generations) has been undemonstrated until now. There is no experimental basis to support the role of transgenerational epigenetics in genome remodeling or to maintain its incidence in the evolution of species, which would mean a return to Lamarckism. We discuss the special influence of transposition, characterized by its randomness and influence on the remodeling of the genome of higher species, more in plants than in animals. Transposition is a phenomenon that influences genome remodeling, with long-term effects. We point out the myths and bioethical consequences derived from a false interpretation of the role of epigenetics as a determinant of the phenotype in the offspring of future generations.

[From transgenesis to gene edition. Bioethical and applied considerations]. / De la transgénesis a la edición génica. Aplicaciones y consideraciones bioéticas.

Transgenesis is a parcel of biotechnology that allows the introduction of genetic information not proper to the genome of living beings, apart from the mechanisms of natural genetic exchange. This made possible to address important applications in bacteria, animals and plants with significant benefits in health, food and environmental aspects. Since its origin, the production of genetically modified organisms (GMOs) caused some controversy due to the possible negative influence of these organisms or their derived products on health and the environment. Over time, genetic modification techniques have renewed, giving way to others of greater precision, simplicity and safety. Currently the CRISPR-Cas9 technique is widely used, which allows to edit, modify or eliminate specific DNA sequences, with multiple applications in the same fields of transgenesis, but adding greater simplicity, security and lower cost. This work presents the main techniques, applications and ethical implications of using these methods and their perspectives in an ever-evolving world. The bacteria for obtaining products of pharmacological interest, new varieties of cultivated plants of higher production, more resistance to growth limiting agents and better nutritional quality and domestic animals modified genetically, offer a set of advantages needed to address the global challenges that affect the lives of many people around the world.

[Epigenetics. Mechanism and significance in gene regulation]. / La epigenética. Sus mecanismos y significado en la regulación génica.

Epigenetics deals with the study of structural modifications in the regions of the genome, by methylation of DNA or chromosomal histones, or other mechanisms that affect the expression of genes without altering the base composition of DNA. Cell differentiation, which is established in embryonic development from blastocyst status, is the consequence of differential cell reprogramming, based on programmed epigenetic modifications, which establish differences in the epigenome of cells and tissues. Maternal and paternal genomes of the gametes have genomic imprinting differences due to DNA methylation or other epigenetic modifications established in the germinal cells during gametogenesis. Maternal and paternal parental genomes present differences of genomic imprinting, which are established by DNA methylation or other epigenetic modifications during embryonic development, in the primordial germ cells. Unscheduled epigenetic modifications may also occur under the influence of uncontrolled environmental factors, which can lead to health disturbances. However, all epigenetic modifications are erased after fertilization and those affecting the germ line of the embryo or fetus during their development are not inherited beyond the second generation, - F2 -. Epigenetics should not be considered a new type of inheritance with transgenerational consequences, but as a set of mechanisms related to genetic regulation.

Perspectivas Biomédicas de la maternidad subrogada / Biomedical perspective of the surrogate motherhood

La maternidad subrogada se refiere a la implantación de un embrión creado por la tecnología de la fecundación in vitro (FIV) en una madre sustituta, o madre gestante, mediante un contrato con ella. Puede implicar a las familias naturales (mujer y hombre) con problemas de infertilidad o no, o a familias monoparentales o biparentales del mismo sexo. Atendiendo al origen de los gametos usados en la FIV surgen diversas situaciones en la relación genética del niño con la madre gestante y los padres comitentes. La maternidad subrogada se planteó en principio como una opción para solucionar problemas de infertilidad. Sin embargo, se ha convertido en una práctica posible y atractiva como fuente de recursos económicos para mujeres pobres. Los casos de maternidad por acuerdo, sin mediar un contrato, son excepcionales y no son apropiadamente "maternidad subrogada" sino de "maternidad altruista" debiendo ser considerados como casos de fertilización in vitro heteróloga. En este artículo se analizan las indicaciones sobre la utilización de la maternidad subrogada. También se tratan los aspectos médicos, genéticos y bioéticos que plantea esta nueva derivación de la fecundación in vitro. Como puntos de especial atención se plantean una serie de preguntas: ¿Se utiliza preferentemente para solucionar problemas de infertilidad?, ¿No es esto en la práctica una nueva forma de utilización de la mujer?, ¿no supone un atentado a la familia natural?, ¿No supone además un atentado a la dignidad de los seres humanos?

The subrogated motherhood takes place when an embryo created by in vitro fertilization (IVF) technology is implanted in a surrogate, sometimes called a gestational mother, by means a contract with her. It can imply to natural families (woman and man) with or without infertility problems, or to monoparental or biparental families of the same sex. Concerning the origin of the gametes used in the IVF emerges different implications on the genetic relationship of the resulting child with the surrogate and the future parents. The subrogated motherhood was initially considered an option to solve infertility problems. Nevertheless this practice has become a possible and attractive option as a source of economic resources for poor women. The cases of benefit of a pregnancy without mediating a contract are exceptional and they are not properly cases of "subrogated maternity" but of "altruistic maternity" and must be considered as heterologous in vitro fertilization. In this article are analyzed the medical, genetic and bioethics aspects of this new derivation of the fertilization in vitro. As points of special attention are considered the following questions: Is it the surrogate motherhood used preferably to solve infertility problems? Is not this actually a new form of exploitation of the woman? Does not suppose an attack to the natural family? Does not suppose in addition an attack to the dignity of the human being?

[Biomedical Perspective of the Surrogate Motherhood]. / Perspectivas Biomédicas de la Maternidad Subrogada.

The subrogated motherhood takes place when an embryo created by in vitro fertilization (IVF) technology is implanted in a surrogate, sometimes called a gestational mother, by means a contract with her. It can imply to natural families (woman and man) with or without infertility problems, or to monoparental or biparental families of the same sex. Concerning the origin of the gametes used in the IVF emerges different implications on the genetic relationship of the resulting child with the surrogate and the future parents. The subrogated motherhood was initially considered an option to solve infertility problems. Nevertheless this practice has become a possible and attractive option as a source of economic resources for poor women. The cases of benefit of a pregnancy without mediating a contract are exceptional and they are not properly cases of ″subrogated maternity″ but of ″altruistic maternity″ and must be considered as heterologous in vitro fertilization. In this article are analyzed the medical, genetic and bioethics aspects of this new derivation of the fertilization in vitro. As points of special attention are considered the following questions: Is it the surrogate motherhood used preferably to solve infertility problems? Is not this actually a new form of exploitation of the woman? Does not suppose an attack to the natural family? Does not suppose in addition an attack to the dignity of the human being?

El consejo genético prenatal / Prenatal genetic counseling

No disponible

[Bioethics and biojuridical evaluation of preimplantation genetic diagnosis in Spain]. / Valoración bioética y biojurídica del diagnóstico genético preimplantatorio en España.

Spanish law 14/2006 introduced the necessary legal platform for scientific use and medical application of preimplantatory genetic diagnosis (PGD) in the Country. Since it was approved, there have been some cases of babies that have been born by artificial reproductive techniques using PGD. The most recent case was the first ″double hope baby″ who was free of beta-thalasemy and a histocompatible donor for his sick older brother. This situation, new in Spain, introduced a new context that confirmed the eugenic consequences of this kind of techniques. This article evaluates PGD starting by a multidisciplinary analysis that covers the technical aspects of PGD and the different arguments which support or detract from it. In summary, the technique involves strong eugenic aspects supported by poor arguments. The need to use valid premises when making legal judgments on biomedical procedures with social consequences, lead us to warn of the consequences of using PGD.

[Congenital defects and incapacity]. / Defectos congénitos y discapacidad.

As a whole the congenital defects constitute an important section of the medical attention affecting near 3% of the population. A 15% of spontaneous abortions take place of which the greater frequency corresponds to the chromosome anomalies (25%) and the monogenic mutations (20%) and in a lesser extent to the effects of teratogenic agents. Between the genetic causes determining the congenital defects the mutations that affect genes acting in the early stages of development occupy a main place. These alterations can affect to homeotic genes or monogenic systems that act during the critical phases of the organogenesis. It seems evident that an alteration in the expression of a necessary gene for the appearance of a morphogenetic change constitutes the angular stone to understand resurging of a malformation or discapacity. In the last years has been demonstrated the importance of the teratogenic or environmental agents on the delicate internal physiological balance during the critical stages of the development. In this context must be included the inductive environmental factors inducing epigenetic modifications in the early stage of the development of the embryos produced by fertilization in vitro.