Genetics (from Ancient Greek γενετικός genetikos, "genitive" and that from γένεσις genesis, "origin"), a discipline of biology, is the science of genes, heredity, and variation in living organisms.
Genetics deals with the molecular structure and function of genes, gene behavior in context of a cell or organism (e.g. dominance and epigenetics), patterns of inheritance from parent to offspring, and gene distribution, variation and change in populations, such as through Genome-Wide Association Studies. Given that genes are universal to living organisms, genetics can be applied to the study of all living systems, from viruses and bacteria, through plants and domestic animals, to humans (as in medical genetics).
The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. However, the modern science of genetics, which attempts to understand the process of inheritance, only began with the work of Gregor Mendel in the mid-19th century. Although he did not know the physical basis for heredity, Mendel observed that organisms inherit traits by way of discrete units of inheritance, which are now called genes.
Genes correspond to regions within DNA, a molecule composed of a chain of four different types of nucleotides—the sequence of these nucleotides is the genetic information organisms inherit. DNA naturally occurs in a double stranded form, with nucleotides on each strand complementary to each other. Each strand can act as a template for creating a new partner strand. This is the physical method for making copies of genes that can be inherited.
The sequence of nucleotides in 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 relationship between nucleotide sequence and amino acid sequence is known as the genetic code. The amino acids in a protein determine how it folds into a three-dimensional shape; this structure is, in turn, responsible for the protein's function. Proteins carry out almost all the functions needed for cells to live. A change to the DNA in a gene can change a protein's amino acids, changing its shape and function: this can have a dramatic effect in the cell and on the organism as a whole.
Although genetics plays a large role in the appearance and behavior of organisms, it is the combination of genetics with what an organism experiences that determines the ultimate outcome. For example, while genes play a role in determining an organism's size, the nutrition and health it experiences after inception also have a large effect.
Read more about Genetics: History
Other articles related to "amino acids, acid, amino acid, genetic":
... sap, which is a more dilute diet than phloem sap as the concentration of sugars and amino acids are 1% of those in the phloem ... Plant sap is an unbalanced diet for aphids as it lacks essential amino acids, which aphids, like all animals, cannot synthesise, and possesses a high osmotic ... Essential amino acids are provided to aphids by bacterial endosymbionts, harboured in special cells, bacteriocytes ...
... of proteins, the degree of similarity between amino acids occupying a particular position in the sequence can be interpreted as a rough measure of how ... of only very conservative substitutions (that is, the substitution of amino acids whose side chains have similar biochemical properties) in a particular region of the sequence, suggest that this ... Although DNA and RNA nucleotide bases are more similar to each other than are amino acids, the conservation of base pairs can indicate a similar functional or structural role ...
... methods for decoding the relationship of mRNA to amino acids, there was still a lot of experimentation required before the entire code was deciphered ... This development sped up the process of assigning code words to amino acids ... By 1966, Nirenberg announced that he had deciphered the sixty-four RNA codons for all twenty amino acids ...
... and activation, whereas the thiolation domain covalently binds the adenylated amino acids to phosphopantetheine, and the condensation domain elongates the peptide chain ... substrates include L-valine, L-leucine, L-alanine, L-glycine, 2-aminobutyric acid, 4-methylthreonine, and D-alanine, which is the starting amino acid in the ... With the adenylation domain, ciclosporin synthetase generates the acyl-adenylated amino acids, then covalently binds the amino acid to phosphopantetheine through a thioester linkage ...
... protein nor a lipid, rather deoxyribonucleic acid (DNA) ... colleagues Colin MacLeod and Maclyn McCarty suggested that DNA was responsible for transferring genetic information ... They also knew that were 20 known amino acids ...
Famous quotes containing the word acids:
“The new American finds his challenge and his love in the traffic-choked streets, skies nested in smog, choking with the acids of industry, the screech of rubber and houses leashed in against one another while the townlets wither a time and die.”
—John Steinbeck (1902–1968)