Different fields of research
Very early, genetics has diversified into several different branches:
The genetics of development studies the molecular components (and the genes that code) involved in the formation of the body from the unicellular stage of fertilized egg. It focuses particularly on the establishment of bilateral symmetry and the mechanisms to move from a simple biological system (single, radial symmetry) to a complex (multicellular, often metamerise, and constructed bodies). It often uses model species to study the formation mechanisms of the body (fruit fly, nematode, zebrafish, chicken);
The genetic studies of hereditary diseases human genetic, segregation in families of patients. It seeks to identify in this way mutations responsible for diseases, to develop treatments to cure them;
The genomics studies the structure, composition and evolution of genomes (entire DNA, three billion base pairs in humans, organized in chromosomes), and attempts to identify patterns in DNA can have a biological (genes, transcribed untranslated units, miRNAs, regulatory units, developers, CNGS, etc.).
the quantitative genetics studies the genetic component explaining the variation in quantitative traits (size, coat color, growth rate, the concentration of a molecule, etc.) and their heritability;
the genetic changes studied the signatures of natural selection on the genome of the species, and attempts to identify the genes that played a key role in adaptation and survival of species in changing environments;
the population genetics studies the forces (and their effects) that influence the genetic diversity of populations and species (mutation, drift, selection) by (among others) the development of mathematical models and statistics.
The inheritance, which is examining the phenotype and tries to determine the genotype underlying is always based on the laws of Mendel. Cell biology and molecular biology are studying the genes and their material (DNA or RNA) within the cell, the cell biology for their expression. The progress of the engineering branch of genetics, genetic engineering, was able to pass the stage of simple study to modify the genome and locate, remove or modify new genes into living organisms: the Genetically Modified Organisms (GMOs). The same advances have opened up a new therapeutic approach: the "gene therapy". This is to introduce new genes into the body to overcome a disability is hereditary.
The trend of increasing genetic knowledge poses several problems ethical linked to cloning, various types of 'eugenics possible, the intellectual property of genes and possible environmental risks related to GMOs, as it also complicates the understanding of functioning of the cellular machinery. Indeed, the more one studies it, the actors are more numerous (DNA, messenger RNA, transfer, microRNAs, etc..) And the reverse stock (splicing, editing, etc..) Between them grows.