Genética humana y embriología

Co-dominance is a genetic phenomenon where both alleles of a gene are expressed simultaneously in the phenotype of a heterozygous individual. Unlike traditional Mendelian inheritance, where one allele dominates the other, co-dominance results in a blending or co-expression of traits. This phenomenon is particularly evident in blood type inheritance, where the ABO system showcases co-dominance between the A and B alleles, leading to distinct blood types. In co-dominant traits, the heterozygous individual exhibits a phenotype that is a unique combination of both alleles, rather than a simple intermediate. This complex interplay between alleles adds a layer of diversity and complexity to genetic inheritance patterns, contributing to the rich tapestry of biological diversity.

Genetic counseling plays a crucial role in providing individuals and families with information about the genetic basis of inherited disorders, aiding in informed decision-making. Autosomal inheritance, referring to the transmission of genetic traits through chromosomes other than the sex chromosomes, is a fundamental aspect of genetic counseling. This paper explores the intricacies of autosomal inheritance and its significance in the context of genetic counseling. The discussion encompasses the basic principles of autosomal inheritance, the types of disorders associated with it, genetic counseling strategies, and the impact of technological advancements on the field. Additionally, the ethical considerations and challenges in autosomal inheritance-related genetic counseling are addressed. This comprehensive examination aims to enhance the understanding of autosomal inheritance in the realm of genetic counseling.

Gastric cancer, a complex and heterogeneous disease, poses a significant global health challenge. This article delves into the intricate world of chromosomal instability in gastric cancer, aiming to provide a comprehensive understanding of its role in the development and progression of this malignancy. We explore the underlying genetic mechanisms, clinical implications, and potential therapeutic avenues associated with chromosomal instability in gastric cancer. The analysis draws upon recent research findings and integrates multidisciplinary perspectives, shedding light on the dynamic genomic landscape that contributes to gastric cancer pathogenesis.

Introduction: Disorders or anomalies of Sex differentiation or Development (DSD),are congenital conditions during which the chromosomal, gonadal, and anatomical sexes are atypical. Cytogenetics and molecular genetics are essential in the classification of these variations by Karyotyping and searching for variants. Thus, we selected 2 patients of female civil status among those sent for diagnosis of a DSD and aim to do karyotype but also to verify the presence of the steroid genic region of the Y chromosome (SRY) by Polymerase Chain Reaction (PCR).

Materials and methods: We proceeded to a peripheral venous blood sample in a heparinized tube for the karyotype, and another tube with Ethylene Diamine Tetra Acetic acid (EDTA) for DNA extraction to search for the presence of the SRY gene by PCR.

Results: At the karyotype, the first patient had a formula 46, XY and the second a formula 46, XX. After PCR amplification of the SRY gene and electrophoretic migration on agarose gel, patient the first patient was SRY (+) and the second SRY (-).

Conclusion: Cytogenetics has a fundamental place in the classification of disorders of sexual development. Our patients could be classified as 46, XY DSD, as 46, XX DSD. The search of the SRY gene by PCR constitutes a good starting point in the molecular search for the etiological diagnosis of these abnormalities or variations in sexual differentiation.