Gene duplication

... Gene duplication occurs when an error in DNA replication leads to the duplication of a region of DNA containing a (generally ... become a pseudogene . The postulate that gene duplication has a major role in evolution was developed in ...

Evolutionary developmental biology

... it come from? Novelty may arise through several methods including gene duplication and gene regulation. Gene duplication allows fixation of a particular cellular or biochemical function at ...

Cancer

... of cancer with drugs ("anticancer drugs") that can destroy cancer cells. It interferes with cell division is various possible ways, e.g. with the duplication of DNA or the seperation of newly formed chromosomes . Most forms of chemotherapy target all rapidly dividing cells and are not specific for ...

Chromosomal crossover

... is an exchange of genes . This outcome is the normal way for crossover to occur. If they break at slightly different loci, the result can be a duplication of genes on one chromosome and a deletion of these on the other. If they break and rejoin on opposite sides of the centromere , the result can be ...

Down syndrome

... of the third copy of the chromosome 21 in cells throughout the body of the affected person. Other Down syndrome disorders are based on the duplication of the same subset of genes (e.g., various translocations of chromosome 21). Depending on the actual etiology , the learning disability may ...

Gene

... regulatory sequences. Typically, he or she will simply attribute it to variations within a gene. Errors during DNA replication may lead to the duplication of a gene, which may diverge over time. Though the two sequences may remain the same or be only slightly altered, they are typically regarded as ...

Homeobox

... changes. Two examples of homeobox mutations in the above-mentioned fruit fly are legs where the antennae should be, and a second pair of wings. duplication of homeobox genes can produce new body segments, and such duplications are likely to have been important in the evolution of segmented animals. ...

Isozyme

... and (2) enzymes that are the product of different alleles of the same gene (described as allozymes ). Isozymes are usually the result of gene duplication , but can also arise from polyploidisation or hybridization . Over evolutionary time, if the function of the new variant remains identical to ...

Major histocompatibility complex

... one of the smallest known MHC regions (19 genes), though most mammals have an MHC structure and composition fairly similar to that of humans. Gene duplication is almost certainly responsible for much of the genic diversity. In humans, the MHC is littered with many pseudogenes . One of the most striking ...

Meiosis

... division (meiosis I and II), each usually accompanied by cell division. Single-stage meiosis has been suggested but not convincingly demonstrated. duplication of chromosomes precedes the process of meiosis (during S phase ). Most animals and plants are normally diploid, and use meiosis to produce sexual ...

Oncogene

... protein expression (through misregulation) an increase of protein stability, prolonging its existence and thus its activity in the cell a gene duplication , resulting in a doubled amount of protein in the cell Oncogene Growth factors Growth factors are usually secreted by a few ...

Polymerase chain reaction

... after he first published his ideas. Mullis's idea was to develop a process by which DNA could be artificially multiplied through repeated cycles of duplication driven by an enzyme called DNA polymerase . DNA polymerase occurs naturally in living organisms, where it functions to duplicate DNA when ...