Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a polypeptide or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains. Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. All organisms have many genes corresponding to various biological traits, some of which are immediately visible, such as eye color or number of limbs, and some of which are not, such as blood type, increased risk for specific diseases, or the thousands of basic biochemical processes that comprise life.

A modern working definition of 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 ". Colloquial usage of the term gene (e.g. "good genes", "hair color gene") may actually refer to an allele: a gene is the basic instruction—a sequence of nucleic acids (DNA or, in the case of certain viruses RNA), while an allele is one variant of that gene. Referring to having a gene for a trait is no longer the scientifically accepted usage. In most cases, all people would have a gene for the trait in question, but certain people will have a specific allele of that gene, which results in the trait variant. Further, genes code for proteins, which might result in identifiable traits, but it is the gene, not the trait, which is inherited.

Read more about Gene:  Gene Expression, DNA Replication and Inheritance, History, Mendelian Inheritance and Classical Genetics, Evolutionary Concept of A Gene, Gene Targeting and Implications, Changing Concept

Other articles related to "gene, genes":

Galactosemia - Cause
... meaning a child must inherit one defective gene from each parent to show the disease ... are carriers, because they inherit one normal gene and one defective gene ...
Gene - Changing Concept
... The concept of the gene has changed considerably (see history section) ... It was also previously believed that one gene makes one protein this concept was overthrown by the discovery of alternative splicing and trans-splicing ... The definition of a gene is still changing ...
Gene Family
... A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions ... One such family are the genes for human haemoglobin subunits the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci ... Genes are categorized into families based on shared nucleotide or protein sequences ...
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