So great is the efficiency of the Mendelian mechanism
of gene recombination that only a minuscule fraction of the potentially possible gene combinations can ever be realized.
Not exact matches
But it is possible to assume that ultimately all biological events are determined by laws, mainly by causal laws, in some cases by laws
of probability (effective in
gene recombination and mutation), the law
of conservation
of energy and the lawful acting
of microphysical constants.
The happenings we know a lot about, thanks to evolutionary biology, particularly
of the last four decades, are the roles
of mutation,
recombination of genes in sexual reproduction resulting in a great diversity
of gene arrangements, and natural selection.
Over time,
recombination is expected to lead to a deterioration
of the
gene pool, a process that seems to have accelerated in bees.
Not least the fact that
gene targeting using homologous
recombination or any other method is not perfect — the added DNA is sometimes inserted into the wrong place in the genome, and the process can trigger other kinds
of mutations too.
The benefits
of sexual
recombination depend on the availability
of lots
of different
genes.
Immunoglobulin K
genes are constructed during lymphocyte differentiation by the joining
of two DNA elements, VK and JK, to form both a VKJK coding unit and a reciprocal
recombination product.
DNA elements are asymmetrically joined during the site - specific
recombination of kappa immunoglobulin
genes
The structural analysis
of a number
of recombinants and the derivation
of secondary
recombination products define some
of the basic features
of the mechanism
of immunoglobulin
gene assembly.
But BRCA is just one
of the many
genes that encode important proteins in the DNA repair pathway known as homologous
recombination,» says the study's lead author, Arielle Heeke, MD, a clinical fellow at Georgetown Lombardi Comprehensive Cancer Center.
David Schatz
of Yale University, who studies the origin
of VDJ
recombination, isn't yet totally convinced the sea urchin
genes are in fact versions
of RAG1 and RAG2.
And although the rest
of Genghis Khan's genome has certainly, if Zerjal and Tyler - Smith are right, made an outsize contribution to the Central Asian
gene pool, it has been chopped to bits and mixed in so thoroughly over the centuries by genetic
recombination that no one today is likely to have his whole suite
of genes for any particular trait.
Domain
recombination resulted in greater diversity in pathway response dynamics than did duplication
of genes,
of single domains, or
of two unlinked domains.
Previously, cancer researchers surmised that since chromosomal ends get swapped in ALT, mutation
of genes that restrain DNA exchange, a process scientists call
recombination, might actually cause the condition (or, to extend the ping - pong metaphor, make cells lose paddle control).
Still, the concentration
of male fertility
genes on the Y chromosome, in multiple copies and «spell - checked» by a novel form
of genetic
recombination, supports a surprising theory.
At the outset, no one could predict that the novel H1N1 virus — a
recombination of human, pig, and avian influenza
genes — would turn out to be more wimp than monster.
While further work will be required to fully understand the mechanism driving the
recombination of Plasmodium falciparum's var
genes, scientists were able to calculate the rate at which it happens.
Recombination refers to the formation
of new combinations
of genes naturally during meiosis, which is a stage
of the cell cycle where chromosomes pair up and undergo exchange.
When a favorable form
of a
gene (allele) lies within a
gene - dense, low
recombination region it requires much more work to bring that favorable allele into an existing variety without also dragging in neighboring
genes that may exist in undesirable forms.
Their strategy, Keller explains, was to determine whether a group
of genes in this area maintained its integrity by avoiding what's called
recombination.
Sure enough, in the fire ants, a group
of about 600
genes surrounding Gp - 9 showed a complete absence
of recombination, the researchers report online today in Nature.
Knowing the location
of gene - dense low -
recombination regions helps with decisions about which
genes to pursue for variety improvement.»
Prior to this work, a long - held view was that the distribution
of genes in the genomes
of barley, wheat and their relatives is such that the
gene - dense regions are only out near the ends
of chromosomes where there is also a high rate
of recombination.
the new information enabled the researchers to clarify aspects
of the barley genome that are important in the context
of genome evolution and for practical use
of genome knowledge by plant breeders and basic researchers — namely, the locations
of gene - rich regions including some that have low
recombination
So, if a
gene lies within a
gene - dense, low -
recombination region, then this means that a much larger number
of progeny from crosses must be examined to find those that derive from rare recombinational events that separate the desired new allele from undesirable forms
of neighboring
genes.
Through a process called
recombination, which had not previously been seen in influenza viruses, parts
of the human and swine virus
genes had joined together to create a totally new antigen, one that human immune systems were unprepared for (Science, 11 May, p. 1041).
Scientists have suspected that, like cells in the immune system, olfactory neurons diversify through
recombination — that is, each cell randomly shuffles its DNA so it carries a slightly different version
of the same
gene.
Much
of this DNA is no longer capable
of moving, but is likely «auditioning» perhaps as a regulator
of gene function or in homologous
recombination, which is a type
of genetic
recombination where the basic structural units
of DNA, nucleotide sequences, are exchanged between two DNA molecules to repair breaks in the DNA strands.
The marriage
of Professors Capecchi and Smithies» homologous
recombination technique with Sir Martin's stem cell discoveries has created the highly versatile new technology
of gene targeting.
from the University
of Washington reported a surprising finding - when delivered via AAV infection,
gene targeting vectors with relatively short (1 kb) homology arms underwent homologous
recombination at a frequency three orders
of magnitude higher than identical targeting vectors delivered through transfection
of naked DNA
Bootscanning analysis revealed no evidence for
recombination of TMAdV with other adenoviruses at either the whole - genome or individual
gene level (Fig.
In that year, Russell and Hirata from the University
of Washington reported a surprising finding - when delivered via AAV infection,
gene targeting vectors with relatively short (1 kb) homology arms underwent homologous
recombination at a frequency three orders
of magnitude higher than identical targeting vectors delivered through transfection
of naked DNA.
We identified human X-linked
genes whose gametologs have been pseudogenized or completely lost from the Y chromosome and inferred which evolutionary forces may be acting to retain
genes on the Y. Although
gene loss appears to be largely correlated with the suppression
of recombination, we observe that X-linked
genes with functional Y homologs evolve under stronger purifying selection and are expressed at higher levels than X-linked
genes with nonfunctional Y homologs.
Antibodies are generated through
recombination of a fixed set
of germline immunoglobulin segments, called V
genes, with other germline immunoglobulin segments.
g (acceleration due to gravity) G (gravitational constant) G star G1.9 +0.3 gabbro Gabor, Dennis (1900 — 1979) Gabriel's Horn Gacrux (Gamma Crucis) gadolinium Gagarin, Yuri Alexeyevich (1934 — 1968) Gagarin Cosmonaut Training Center GAIA Gaia Hypothesis galactic anticenter galactic bulge galactic center Galactic Club galactic coordinates galactic disk galactic empire galactic equator galactic habitable zone galactic halo galactic magnetic field galactic noise galactic plane galactic rotation galactose Galatea GALAXIES galaxy galaxy cannibalism galaxy classification galaxy formation galaxy interaction galaxy merger Galaxy, The Galaxy satellite series Gale Crater Galen (c. AD 129 — c. 216) galena GALEX (Galaxy Evolution Explorer) Galilean satellites Galilean telescope Galileo (Galilei, Galileo)(1564 — 1642) Galileo (spacecraft) Galileo Europa Mission (GEM) Galileo satellite navigation system gall gall bladder Galle, Johann Gottfried (1812 — 1910) gallic acid gallium gallon gallstone Galois, Évariste (1811 — 1832) Galois theory Galton, Francis (1822 — 1911) Galvani, Luigi (1737 — 1798) galvanizing galvanometer game game theory GAMES AND PUZZLES gamete gametophyte Gamma (Soviet orbiting telescope) Gamma Cassiopeiae Gamma Cassiopeiae star gamma function gamma globulin gamma rays Gamma Velorum gamma - ray burst gamma - ray satellites Gamow, George (1904 — 1968) ganglion gangrene Ganswindt, Hermann (1856 — 1934) Ganymede «garbage theory»,
of the origin
of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson gauge theory gauss (unit) Gauss, Carl Friedrich (1777 — 1855) Gaussian distribution Gay - Lussac, Joseph Louis (1778 — 1850) GCOM (Global Change Observing Mission) Geber (c. 720 — 815) gegenschein Geiger, Hans Wilhelm (1882 — 1945) Geiger - Müller counter Giessler tube gel gelatin Gelfond's theorem Gell - Mann, Murray (1929 ---RRB- GEM «gemination,»
of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone
gene gene expression
gene mapping
gene pool
gene therapy
gene transfer General Catalogue
of Variable Stars (GCVS) general precession general theory
of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic
recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission
of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time geology GEOLOGY AND PLANETARY SCIENCE geomagnetic field geomagnetic storm geometric mean geometric sequence geometry GEOMETRY geometry puzzles geophysics GEOS (Geodetic Earth Orbiting Satellite) Geosat geostationary orbit geosynchronous orbit geosynchronous / geostationary transfer orbit (GTO) geosyncline Geotail (satellite) geotropism germ germ cells Germain, Sophie (1776 — 1831) German Rocket Society germanium germination Gesner, Konrad von (1516 — 1565) gestation Get Off the Earth puzzle Gettier problem geyser g - force GFO (Geosat Follow - On) GFZ - 1 (GeoForschungsZentrum) ghost crater Ghost Head Nebula (NGC 2080) ghost image Ghost
of Jupiter (NGC 3242) Giacconi, Riccardo (1931 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch Giant Magellan Telescope giant molecular cloud giant planet giant star Giant's Causeway Giauque, William Francis (1895 — 1982) gibberellins Gibbs, Josiah Willard (1839 — 1903) Gibbs free energy Gibson, Edward G. (1936 ---RRB- Gilbert, William (1544 — 1603) gilbert (unit) Gilbreath's conjecture gilding gill gill (unit) Gilruth, Robert R. (1913 — 2000) gilsonite gimbal Ginga ginkgo Giotto (ESA Halley probe) GIRD (Gruppa Isutcheniya Reaktivnovo Dvisheniya) girder glacial drift glacial groove glacier gland Glaser, Donald Arthur (1926 — 2013) Glashow, Sheldon (1932 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch Global Astrometric Interferometer for Astrophysics (GAIA) Global Oscillation Network Group (GONG) Globalstar globe Globigerina globular cluster globular proteins globule globulin globus pallidus GLOMR (Global Low Orbiting Message Relay) GLONASS (Global Navigation Satellite System) glossopharyngeal nerve Gloster E. 28/39 glottis glow - worm glucagon glucocorticoid glucose glucoside gluon Glushko, Valentin Petrovitch (1908 — 1989) glutamic acid glutamine gluten gluteus maximus glycerol glycine glycogen glycol glycolysis glycoprotein glycosidic bond glycosuria glyoxysome GMS (Geosynchronous Meteorological Satellite) GMT (Greenwich Mean Time) Gnathostomata gneiss Go Go, No - go goblet cell GOCE (Gravity field and steady - state Ocean Circulation Explorer) God Goddard, Robert Hutchings (1882 — 1945) Goddard Institute for Space Studies Goddard Space Flight Center Gödel, Kurt (1906 — 1978) Gödel universe Godwin, Francis (1562 — 1633) GOES (Geostationary Operational Environmental Satellite) goethite goiter gold Gold, Thomas (1920 — 2004) Goldbach conjecture golden ratio (phi) Goldin, Daniel Saul (1940 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon GOMS (Geostationary Operational Meteorological Satellite) gonad gonadotrophin - releasing hormone gonadotrophins Gondwanaland Gonets goniatite goniometer gonorrhea Goodricke, John (1764 — 1786) googol Gordian Knot Gordon, Richard Francis, Jr. (1929 — 2017) Gore, John Ellard (1845 — 1910) gorge gorilla Gorizont Gott loop Goudsmit, Samuel Abraham (1902 — 1978) Gould, Benjamin Apthorp (1824 — 1896) Gould, Stephen Jay (1941 — 2002) Gould Belt gout governor GPS (Global Positioning System) Graaf, Regnier de (1641 — 1673) Graafian follicle GRAB graben GRACE (Gravity Recovery and Climate Experiment) graceful graph gradient Graham, Ronald (1935 ---RRB- Graham, Thomas (1805 — 1869) Graham's law
of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) Granat Grand Tour grand unified theory (GUT) Grandfather Paradox Granit, Ragnar Arthur (1900 — 1991) granite granulation granule granulocyte graph graph theory graphene graphite GRAPHS AND GRAPH THEORY graptolite grass grassland gravel graveyard orbit gravimeter gravimetric analysis Gravitational Biology Facility gravitational collapse gravitational constant (G) gravitational instability gravitational lens gravitational life gravitational lock gravitational microlensing GRAVITATIONAL PHYSICS gravitational slingshot effect gravitational waves graviton gravity gravity gradient gravity gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) gray goo gray matter grazing - incidence telescope Great Annihilator Great Attractor great circle Great Comets Great Hercules Cluster (M13, NGC 6205) Great Monad Great Observatories Great Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square
of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases Green's theorem Greg, Percy (1836 — 1889) Gregorian calendar Grelling's paradox Griffith, George (1857 — 1906) Griffith Observatory Grignard, François Auguste Victor (1871 — 1935) Grignard reagent grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track group group theory GROUPS AND GROUP THEORY growing season growth growth hormone growth hormone - releasing hormone growth plate Grudge, Project Gruithuisen, Franz von Paula (1774 — 1852) Grus (constellation) Grus Quartet (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH215)
Approximately 50 %
of epithelial ovarian cancers (EOC) exhibit defective DNA repair via homologous
recombination (HR) due to genetic and epigenetic alterations
of HR pathway
genes.
The paper, entitled «Sequence Variants in the RNF212
Gene Associate with Genomewide
Recombination Rate,» is published today in the online edition
of Science, at www.sciencemag.org/sciencexpress.
A Phase III, Open Label, Randomized Study to Assess the Efficacy and Safety
of Olaparib (Lynparza) versus Enzalutamide or Abiraterone Acetate in Men with Metastatic Castration - Resistant Prostate Cancer who have Failed Prior Treatment with a New Hormonal Agent and have Homologous
Recombination Repair
Gene Mutations.
Independent control
of immunoglobulin switch
recombination at individual switch regions evidenced through Cre — loxP — mediated
gene targeting.
Both
genes function in the homologous
recombination (HR) pathway
of the DNA double - strand break (DSB) repair...
Large - scale genomic studies have shown that half
of epithelial ovarian cancers (EOCs) have alterations in
genes regulating homologous
recombination (HR) repair.
The SNPs, referred to as rs3796619 and rs1670533, are within the RNF212
gene, and are estimated to account for approximately 22 %
of paternal variability in
recombination and 6.5 %
of maternal variability.
Little is known about RNF212, though it is a mammalian homolog
of a
gene called ZHP - 3 known to be crucial for the success
of recombination in other organisms.
If you look at the most clear indication
of homologous
recombination deficiency — loss
of BRCA1 or BRCA2 cancer
genes, either in the inherited germline or the tumor itself — that number is close to 25 %
of ovarian cancers.
Testing for additional
genes in the pathway and in a number
of pathways is done through a number
of commercial resources; the only other clinically relevant test is the homologous
recombination defect assay, which is commercially available from Myriad Genetics.
BRCA1 is a tumour suppressor
gene involved in DNA repair through homologous
recombination and in preserving the integrity
of the genome.
By studying two species
of fruit flies, they discovered a
gene, MEI - 218, that controls the rate
of recombination.
These
genes are assembled by DNA
recombination and code for proteins that are a crucial part
of antibodies, produced in antibody - secreting lymphocytes or B - cells.
Characterized the role
of biased
gene conversion, a non-adaptive
recombination associated process, in shaping the fastest evolving regions
of the human genome.
Hypothetical roles
of the methyltransferase could involve any
of the following: 1) the epigenetic control
of differential pir
gene expression in acute and chronic infections50, 2) the sequence may have a role in genome stability and
recombination, or 3) this could be a selfish
gene that was able to transpose.