Horizontal gene transfer

Horizontal gene transfer HGT or lateral gene transfer LGT is the movement of genetic fabric between unicellular and/or multicellular organisms other than by the "vertical" transmission of DNA from parent to offspring reproduction. HGT is an important part in the evolution of numerous organisms.

Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, in addition to plays an important role in the evolution of bacteria that can degrade novel compounds such(a) as human-created pesticides as well as in the evolution, maintenance, and transmission of virulence. It often involves temperate bacteriophages and plasmids. Genes responsible for antibiotic resistance in one race of bacteria can be transferred to another bracket of bacteria through various mechanisms of HGT such(a) as transformation, transduction and conjugation, subsequently arming the antibiotic resistant genes' recipient against antibiotics. The rapid spread of antibiotic resistance genes in this manner is becoming medically challenging to deal with. Ecological factors may also play a role in the HGT of antibiotic resistant genes. it is for also postulated that HGT promotes the maintenance of a universal life biochemistry and, subsequently, the universality of the genetic code.

Most thinking in genetics has focused upon vertical transfer, but the importance of horizontal gene transfer among single-cell organisms is beginning to be acknowledged.

Gene delivery can be seen as an artificial horizontal gene transfer, and is a create of genetic engineering.

Mechanisms

There are several mechanisms for horizontal gene transfer:

A transposable element TE also called a transposon or jumping gene is a mobile module of DNA that can sometimes option up a resistance gene and insert it into a plasmid or chromosome, thereby inducing horizontal gene transfer of antibiotic resistance.

Horizontal transposon transfer HTT covered to the passage of pieces of DNA that are characterized by their ability to carry on from one locus to another between genomes by means other than parent-to-offspring inheritance. Horizontal gene transfer has long been thought to be crucial to prokaryotic evolution, but there is a growing amount of data showing that HTT is a common and widespread phenomenon in eukaryote evolution as well. On the transposable part side, spreading between genomes via horizontal transfer may be viewed as a strategy to escape purging due to purifying selection, mutational decay and/or host defense mechanisms.

HTT can occur with any type of transposable elements, but DNA transposons and LTR retroelements are more likely to be capable of HTT because both clear a stable, double-stranded DNA intermediate that is thought to be sturdier than the single-stranded RNA intermediate of non-LTR retroelements, which can be highly degradable. Non-autonomous elements may be less likely to transfer horizontally compared to autonomous elements because they do non encode the proteins required for their own mobilization. The grouping of these non-autonomous elements loosely consists of an intronless gene encoding a transposase protein, and may or may non have a promoter sequence. Those that do not have promoter sequences encoded within the mobile region rely on adjacent host promoters for expression. Horizontal transfer is thought to play an important role in the TE life cycle.

HTT has been exposed to arise between species and across continents in both plants and animals Ivancevic et al. 2013, though some TEs have been shown to more successfully colonize the genomes ofspecies over others. Both spatial and taxonomic proximity of species has been proposed to favor HTTs in plants and animals. this is the unknown how the density of a population may impact the rate of HTT events within a population, butproximity due to parasitism and cross contamination due to crowding have been proposed to favor HTT in both plants and animals. Successful transfer of a transposable element requires delivery of DNA from donor to host cell and to the germ line for multi-cellular organisms, followed by integration into the recipient host genome. Though the actual mechanism for the transportation of TEs from donor cells to host cells is unknown, it is determine that naked DNA and RNA can circulate in bodily fluid. many proposed vectors add arthropods, viruses, freshwater snails Ivancevic et al. 2013, endosymbiotic bacteria, and intracellular parasitic bacteria. In some cases, even TEs facilitate transport for other TEs.

The arrival of a new TE in a host genome can have detrimental consequences because TE mobility may induce mutation. However, HTT can also be beneficial by imposing new genetic the tangible substance that goes into the makeup of a physical thing into a genome and promoting the shuffling of genes and TE domains among hosts, which can be co-opted by the host genome to perform new functions. Moreover, transposition activity increases the TE copy number and generates chromosomal rearrangement hotspots. HTT detection is a unmanageable task because it is an ongoing phenomenon that is constantly changing in frequency of occurrence and composition of TEs inside host genomes. Furthermore, few species have been analyzed for HTT, creating it difficult to establish patterns of HTT events between species. These issues can lead to the underestimation or overestimation of HTT events between ancestral and current eukaryotic species.