students Logo
Home | Sitemap | Contact us | Search | Language
Left Right
  Home >> Molecular Biology Dictionary >>Dominant Marker Selection - Doubler Recessive

Dominant marker selection
Selection of cells via a gene coding a product that enables only the cells that carry the gene to grow under particular conditions. For example, plant and animal cells
that express the introduced Neor gene are resistant to the compound G418, while cells that do not carry e Neor gene are killed by G418. a.k.a. positive selection; see also positive selectable marker.

Dominant selectable marker gene
A gene that allows the host ell to survive under conditions where it would otherwise die

Dominant (-acting) oncogene
A gene that stimulates cell proliferation and cogenesis to oncogenesis when present in donor plant (mother plant) as a source of plant material a.k.a. ortet. cf explant.

 

Doping
The intentional alloying of semiconducting materials with controlled concentrations of donor or acceptor impurities
Dormancy
(F. dormir, from L. dormire the life of an animal or plant completely ceases. Physiological changes associated with dormancy help the organism survive adverse environmental conditions. Annual plants survive the winter as dormant seeds, while many perennial plants survive as dormant tubers, rhizomes, or bulbs. Hibernation and aestivation in animals help them survive extremes of cold and heat, respectively. cf rest period

Dosage compensation
A phenomenon whereby inactivation of all but one of the X chromosomes in female mammals results in males and females producing the same quantity of peptide from X-linked genes

Dot blot
A technique for measuring the amount of one specific DNA or RNA in a complex mixture. The samples are spotted onto a hybridization membrane (such as nitrocellulose or activated nylon, etc.), fixed and hybridized with a radioactive probe. The extent of labeling (as determined by autoradiography and densitometry) is proportional to the concentration of the target molecule in the sample. Standards provide a means of calibrating the results

Double crossing-over
Two simultaneous reciprocal breakage and reunion events between the same two chromatids.

Double helix
Describes the coiling of the antiparallel strands of the DNA molecule, resembling a spiral staircase in .which the paired bases form the steps and the sugar-phosphate backbones form the rails.

Double fertilization
A process, unique to flowering plants, in which two male nuclei, which have travelled down the pollen tube, separately fuse with different female nuclei in the embryo sac. The first male nucleus fuses with the egg cell to form the zygote; the second male nucleus fuses with the two polar nuclei to form a triploid nucleus that develops into the endosperm.

Double recessive
An organism homozygous for a recessive allele at each of two loci.

 

Left Right