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A gene is a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions. The physical development and phenotype of organisms can be thought of as a product of genes interacting with each other and with the environment. A concise definition […]
One of the most fundamental technologies developed to study genetics, DNA sequencing allows researchers to determine the sequence of nucleotides in DNA fragments. Developed in 1977 by Frederick Sanger and coworkers, chain-termination sequencing is now routinely used to sequence DNA fragments. With this technology, researchers have been able to study the molecular sequences associated with […]
A variety of techniques exist for manipulating DNA in the laboratory. Restriction enzymes are a commonly used enzyme that cuts DNA at specific sequences, producing predictable fragments of DNA.The use of ligation enzymes allows these fragments to be stitched back together, and by ligating fragments of DNA together from different sources, researchers can create recombinant […]
Medical genetics research seeks to find and study the genetic causes of human diseases.[48] When searching for an unknown gene that may be involved in a disease, researchers commonly use genetics linkage and genetic pedigree charts to find the location on the genome associated with the disease. At the population level, researchers take advantage of […]
Although geneticists originally studied inheritance in a wide range of organisms, researchers began to specialize in studying the genetics of a particular subset of organisms. The fact that significant research already existed for a given organism would encourage new researchers to choose it for further study, and so eventually a few “model organisms” became the […]
Mutations produce organisms with different genotypes, and those differences can result in different phenotypes. Many genetic mutations, called “neutral mutations”, have a negligible effect on an organism’s phenotype, health, and reproductive fitness. Mutations which do have an effect are often deleterious, but occasionally mutations arise which are beneficial in the current environmental context of the […]
During the process of DNA replication, errors occasionally occur in the polymerization of the second strand (these error rates are generally extremely low, 1 error in every 10-100 million bases).These errors, called mutations, can have an impact on the phenotype of an organism, especially if they occur within the protein coding sequence of a gene. […]
The genome of a given organism contains thousands of genes, but not all these genes need to be active at any given moment. A gene is “expressed” when it is being transcribed into mRNA (and translated into protein), and there exist many cellular methods of controlling the expression of genes such that proteins are produced […]
Although genes contain all the information an organism uses to function, the environment plays an important role in determining the ultimate phenotype — a dichotomy often referred to as “nature vs. nurture”. The phenotype of an organism depends on the interaction of genetics with the environment. One example of this is the case of temperature-sensitive […]
Genes generally express their functional effect through the production of proteins, which are complex molecules responsible for most functions in the cell. Proteins are chains of amino acids, and the DNA sequence of a gene (through an RNA intermediate) is used to produce a specific protein sequence. Each group of three nucleotides in the sequence, […]
