Genetics
The genetics (from the ancient Greek: γενετικός, guennetikós, 'genitive', and this from γένεσις, genesis, 'origin') is the area of study of biology that seeks to understand and explain how biological inheritance is transmitted from generation to generation through DNA. It is one of the fundamental areas of modern biology, encompassing within it a large number of its own and interdisciplinary disciplines that are directly related to biochemistry, medicine, and cell biology.
The main object of study in genetics are genes, made up of segments of DNA and RNA, after the transcription of messenger RNA, ribosomal RNA and transfer RNA, which are synthesized from DNA. DNA controls the structure and function of each cell, it has the ability to create exact copies of itself through a process called replication.
First genetic studies
Gregor Johann Mendel (July 20, 1822 – January 6, 1884) was an Augustinian Catholic monk and naturalist born in Heinzendorf, Austria (present-day Hynčice, Nový Jičín district, Czech Republic) who discovered, through experimentation of mixtures of different varieties of peas, peas or peas (Pisum sativum), the so-called Mendel's Laws that gave rise to genetic inheritance.
In 1941 Edward Lawrie Tatum and George Wells Beadle demonstrated that messenger RNA genes code for proteins; then in 1953 James D. Watson and Francis Crick determined that the structure of DNA is a double helix in antiparallel directions, polymerized in the 5' direction. to 3', for the year 1977 Frederick Sanger, Walter Gilbert, and Allan Maxam sequenced the complete DNA of the bacteriophage genome and in 1990 the Human Genome Project was founded.
The Science of Genetics
Although genetics play a very significant role in the appearance and behavior of organisms, it is the combination of genetics, replication, transcription and processing (RNA maturation) with the organism's experiences that determines the final outcome..
Genes correspond to regions of DNA or RNA, two molecules composed of a chain of four different types of nitrogenous bases (adenine, thymine, cytosine and guanine in DNA), in which after transcription (RNA synthesis) are it changes thymine to uracil—the sequence of these nucleotides is the genetic information that organisms inherit. DNA naturally exists in a double-stranded form, that is, in two strands in which the nucleotides of one strand complement those of the other.
The nucleotide sequence of a gene is translated by cells to produce a chain of amino acids, creating proteins—the order of amino acids in a protein corresponds to the order of nucleotides in the gene. This is called the genetic code. The amino acids in a protein determine how it folds into a three-dimensional shape and is responsible for the protein's function. Proteins carry out almost all the functions that cells need to live.
The genome is the totality of genetic information possessed by a particular organism. In general, when talking about the genome in eukaryotic beings, it refers only to the DNA contained in the nucleus, organized in chromosomes, but the mitochondria also contains genes and is called the mitochondrial genome.
Subdivisions of Genetics
Genetics is subdivided into several branches, such as:
- Cytogenetics: The central axis of this discipline is the study of chromosome and its dynamics, as well as the study of the cell cycle and its impact on inheritance. It is very linked to the biology of reproduction and cell biology.
- Classical or Mendelian: It is based on Mendel's laws to predict the inheritance of certain characters or diseases. Classical genetics also analyzes how the phenomenon of recombination or ligation alter the expected results according to Mendel's laws.
- Quantitative: Analyzes the impact of multiple genes on phenotype, especially when these have small-scale effects.
- Philogeny: It is the genetic that studies kinship among the different taxa of living beings.
- Clinical genetics: Applies genetics to diagnose pathologies of genetic origin.
- Preventive Genetics: Makes use of genetics to show the different predispositions that can be given to various factors.
- Population Genetics: It is concerned about the behavior of genes in a population and how this determines the evolution of organisms.
- Development Genetics: Study how genes are regulated to form a complete organism from an initial cell.
- Molecular Genetics: Study DNA, its composition and the way it duplicates. Likewise, it studies the role of genes from the molecular point of view: As they transmit their information until they reach synthesize proteins.
- Mutagénesis: Study the origin and impact of mutations on different levels of genetic material.
Genetic engineering
Genetic engineering is the specialty that uses technology for the manipulation and transfer of DNA from one organism to another, making it possible to control some of its genetic properties. Through genetic engineering, qualities of organisms can be enhanced and eliminated in the laboratory (see Genetically Modified Organism). For example, genetic defects can be corrected (gene therapy), antibiotics can be made in the mammary glands of farm cows, or animals such as Dolly the sheep can be cloned.
Some of the ways to control this is through transfection (lysing cells and using free genetic material), conjugation (plasmids), and transduction (using phages or viruses), among other ways. In addition, you can see how to regulate this gene expression in organisms.
Regarding the aforementioned gene therapy, it must be said that no successful treatment has yet been achieved in humans to cure any disease. All investigations are in the experimental phase. Because the way the therapy works has yet to be discovered (perhaps by applying different methods to introduce the DNA), fewer and fewer funds are dedicated to this type of research. On the other hand, although this is a field that can generate many economic benefits, this type of therapy is very expensive, so as soon as the technique is improved and its cost reduced, it is to be assumed that the investments will rise.
Muscle genetics
Current research states that metabolic markers between different types of muscle genetics can differ by 7-18%. The main difference is found in the body's reaction to carbohydrate intake and the levels of sex hormones such as testosterone.
Muscle genetics is an area of science with potential tools to improve performance in sport. Determining the genetic predisposition of an individual: ectomorph, mesomorph or endomorph, is a strategy used by sports professionals to increase performance. There have been differences in the concentration of creatine in the different types of body somatotypes as well as differences in the concentrations of different metabolic markers.
Timeline of Notable Genetic Discoveries
| Year | Development |
|---|---|
| 1865 | Gregor Mendel's work is published |
| 1900 | The botanists Hugo de Vries, Carl Correns and Erich von Tschermak rediscover Gregor Mendel's work |
| 1903 | The involvement of chromosomes in inheritance is discovered |
| 1905 | British biologist William Bateson coins the term "Genetics". |
| 1910 | Thomas Hunt Morgan shows that genes reside in chromosomes. Moreover, thanks to the phenomenon of genetic recombination he managed to describe the position of various genes in chromosomes. |
| 1913 | Alfred Sturtevant creates the first genetic map of a chromosome |
| 1918 | Ronald Fisher publishes On the correlation between relatives on the supposition of Mendelian inheritance — modern synthesis begins. |
| 1923 | Genetic maps demonstrate the linear disposition of genes in chromosomes |
| 1928 | It is called mutation to any change in the nucleotide sequence of a gene, whether it is evident or not in the phenotype |
| 1928 | Fred Griffith discovers a transmissible hereditary molecule between bacteria (see Griffith Experiment) |
| 1931 | Crossing is the cause of recombination |
| 1941 | Edward Lawrie Tatum and George Wells Beadle demonstrate that genes encode proteins; see the central dogma of Biology |
| 1944 | Oswald Theodore Avery, Colin McLeod and Maclyn McCarty demonstrate that DNA is the genetic material (called then transformative principle) |
| 1950 | Erwin Chargaff shows that the proportions of each nucleotide follow some rules (e.g., that the amount of adenine, A, tends to be equal to the amount of timina, T). Barbara McClintock discovers the transposons in the corn |
| 1952 | Hershey and Chase's experiment shows that the genetic information of the fagos resides in DNA |
| 1953 | James D. Watson and Francis Crick determine that the DNA structure is a double propeller |
| 1956 | Joe Hin Tjio and Albert Levan establish that, in the human species, the number of chromosomes is 46 |
| 1958 | Meselson and Stahl's experiment shows that DNA replication is semi-conservative replication |
| 1961 | Genetic code is organized in triplets |
| 1964 | Howard Temin demonstrates, using RNA virus, exceptions to Watson's central dogma |
| 1970 | Restraining enzymes are discovered in the bacteria Haemophilius influenzae, allowing scientists to manipulate DNA |
| 1973 | The study of cell lineages through clonal analysis and the study of homeotic mutations led to the theory of compartments proposed by Antonio García-Bellido et al.. According to this theory, the body is composed of compartments or units defined by the action of master genes that execute decisions that lead to several cell clones towards a development line. |
| 1977 | Fred Sanger, Walter Gilbert, and Allan Maxam, sequencing DNA for the first time working independently. The Sanger lab completes the sequence of the bacteriophagus genome Ω-X174 |
| 1983 | Kary Banks Mullis discovers the chain reaction of the polymerase, which allows the amplification of DNA |
| 1989 | Francis Collins and Lap-Chee Tsui sequence a human gene for the first time. The gene encodes the CFTR protein, whose defect causes cystic fibrosis |
| 1990 | The Human Genome Project was founded by the United States Department of Energy and Health Institutes |
| 1995 | The genome of Haemophilus influenzae is the first sequenced genome of a free life organism |
| 1996 | The complete sequence of an eucariot, the yeast is first known Saccharomyces cerevisiae |
| 1998 | The complete sequence of a multicellular eukaryate, nematode, is first known Caenorhabditis elegans |
| 2001 | The Genomics Human Genome Project presents the first draft of the human genome sequence |
| 2003 | (14 April) The Human Genome Project is successfully completed with 99 % of the genome sequenced with a precision of 99,99 % |
Additional bibliography
- Alberts, Bruce; Bray, Dennis; Hopkin, Karen; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter (2013). Essential Cell Biology, 4th Edition (in English). Garland Science. ISBN 978-1-317-80627-1.
- Griffiths, Anthony J.F.; Miller, Jeffrey H.; Suzuki, David T.; Lewontin, Richard C.; Gelbart, eds. (2000). An Introduction to Genetic Analysis (in English) (7th edition). New York: W. H. Freeman. ISBN 978-0-7167-3520-5.
- Hartl D, Jones E (2005). Genetics: Analysis of Genes and Genomes (in English) (6th edition). Jones & Bartlett. ISBN 978-0-7637-1511-3.
- King, Robert C; Mulligan, Pamela K; Stansfield, William D (2013). A Dictionary of Genetics (in English) (8th edition). New York: Oxford University Press. ISBN 978-0-19-976644-4.
- Lodish H, Berk A, Zipursky LS, Matsudaira P, Baltimore D, Darnell J (2000). Molecular Cell Biology (in English) (4th edition). New York: Scientific American Books. ISBN 978-0-7167-3136-8.