Читать книгу Algorithms in Bioinformatics - Paul A. Gagniuc - Страница 47

Understanding of the mechanisms and vectors underpinning HGT across the kingdoms of life is still limited. Mobile genetic elements (MGEs) represent the main known vectors for HGT [137]. Well-known HGT events often include, but are not limited to, transposable elements (TE), plasmids or bacteriophage elements [141]. The behavior of a MGE has a certain degree of stochasticity and may incorporate a complete gene(s) or may include only sections of a gene, or with a high probability none of the two. Sections of genes transferred by MGEs decay in time and are recognized in bioinformatic analyzes as pseudogenes (nonfunctional genes) [126]. Among the MGEs, TE can best show the level of complexity that a DNA fragment can exhibit. The TE were first observed in Zea mays (corn) by Barbara McClintock in 1950 [142]. The main observation made by Barbara McClintock was that the genetic material can jump from one place to another within a genome. The insertion of TEs into the coding pigment-genes was responsible for unstable phenotypes on the kernels of a maize ear (kernels of different colors). Note that each kernel is an embryo produced from an individual fertilization and one ear of corn contains around 800 kernels positioned in 16 rows.