When a certain gene is known to cause a disease, we refer to it as a single gene disorder or a Mendelian disorder.
Share. Genes are often called the blueprint for life, because they tell each of your cells what to do and when to do it: be a muscle, make bone, carry nerve signals, and so on. Single gene disorders are caused by DNA changes in one particular gene, and often have predictable inheritance patterns. 1  Over 10,000 human disorders are caused by a change, known as a mutation, in a single gene. 1 Dominant diseases are single gene disorders that occur in the heterozygous state – when an individual has one mutant copy of the relevant gene and one healthy copy. 2  The effects of the mutant version of the gene (allele) override the effects of the healthy version of the gene. Single Gene Disorders. When a certain gene is known to cause a disease, we refer to it as a single gene disorder or a Mendelian disorder. For example, you may have heard of cystic fibrosis, sickle cell disease, Fragile X syndrome, muscular dystrophy, or Huntington disease. These are all examples of single gene d Introduction. Quiz. If the changes in a genome are restricted to a single gene, a single-gene defect ensues. Usually this involves a point mutation and leads to an altered amino acid sequence in the proteins that are coded in this section of the DNA.  Figure 1: Diagram of pleiotropy. A pleiotropic gene is a single gene that controls more than one trait. © 2008 Nature Education All rights reserved. Today, we know that Mendel's observations were the result of pleiotropy, or the phenomenon in which a single gene contributes to multiple phenotypic traits. Pleiotropy should not be confused with polygenic traits, in which multiple genes converge to result in a single phenotype. In some instances of pleiotropy, the influence of the single gene may be direct. For example, if a mouse is born blind due to any number of single-gene traits (Chang et al. , 2002), it is not surprising that this mouse would also do poorly in visual learning task A single gene trait is controlled by a single gene. Polygenic traits are controlled by two or more than two genes on different chromosomes. These genes are described as polyge … nes. Examples of human polygenic inheritance are height, skin color and weight. Polygenes allow a wide range of physical traits. Hairline, either straight or widow's peak, is a trait governed by a single gene. Another trait controlled by a single gene is the ability or inability to roll the tongue into … a U shape. 1  The Five Major Parts of the Brain At its most basic, the brain controls the body. A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes.  Alternative splicing is a regulated process during gene expression that results in a single gene coding for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. Alternative splicing occurs as a normal phenomenon in eukaryotes, where it greatly increases the biodiversity of proteins that can be encoded by the genome; in humans, ~95% of multi-exonic genes are alternatively spliced. A gene is a segment of DNA that encodes function. A chromosome consists of a long strand of DNA containing many genes. A human chromosome can have up to 500 million base pairs of DNA with thousands of genes. These alleles encode slightly different versions of a protein, which cause different phenotype traits. Colloquial usage of the term having a gene (e.g., good genes, hair colour gene) typically refers to having a different allele of the gene.
http://genetics.thetech.org/about-genetics/how-do-genes-work http://www.yourgenome.org/facts/what-are-single-gene-disorders http://hihg.med.miami.edu/thromboticstorm/genetics-overview/single-gene-disorders http://www.embryology.ch/anglais/kchromaber/einzeln01.html http://www.nature.com/scitable/topicpage/Pleiotropy-One-Gene-Can-Affect-Multiple-Traits-569 http://www.answers.com/Q/What_is_a_single-gene_trait http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation https://en.wikipedia.org/wiki/Alternative_splicing https://en.wikipedia.org/wiki/Gene
what does a single gene do?