Human genetics
In humans, the transmission mechanisms of hereditary traits occur in the same way as in other living beings. Genes are transmitted from parents to descendants, and the differences between individuals are a consequence of their genes from the influence of the environment. Genetic characteristics can vary depending on how the environment influences, for example, improving with a healthy lifestyle, but the effects produced on the phenotype due to the environment alone are not transmitted to the offspring.
Although the same experiments cannot be done in people as in animals, since crosses cannot be planned to check what the offspring is like, the family history of some characteristics or alterations that appear in people of the same family can be analyzed.
Heredity in the human species
Humans have 46 chromosomes, 23 pairs, in all somatic cells, since we are diploid (2n). The only haploid cells (n) are the gametes (ovules and sperm), which only have 23 chromosomes, since when they unite in fertilization, they will give rise to an individual with all 46 chromosomes (2n). In the gametes are the genes with the necessary information for the hereditary characteristics of the new individual.
Nonsex chromosomes, common in both sexes, are called autosomes. The sex chromosomes or heterocromosomas are homologous in females (XX) and different in males (XY). The Y chromosome is much smaller than the X chromosome and contains fewer genes than the X chromosome.
The karyotype is the set of all the chromosomes of the cell. In it you can see their number and the appearance (in metaphase) of the chromosomes that characterize the species. By analyzing the karyotype, numerical and structural abnormalities can be analyzed.
When represented graphically, in drawing or photograph, karyotype, with numbered and ordered pairs of homologous chromosomes sizes and shapes, the obtained cariogram or ideogram.
