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(cell and molecular biology)
The portion of the chromosomes that stains with low intensity, uncoils during interphase, and condenses during cell division.



(also active chromatin), the portion of the chromatin that retains the uncoiled form of elementary deoxyribonucleoprotein (DNP) threads in the interval between cell divisions (that is, in the interphase), as opposed to the portion of the chromatin known as heterochromatin, which retains the coiled form. Euchromatin also differs from heterochromatin in that it participates in the intensive synthesis of ribonucleic acid (RNA) and contains a larger quantity of nonhistone proteins. Euchromatin contains not only DNP but also ribonucleoprotein granules, which have a diameter of 200–500 angstroms and serve to complete the maturation of the RNA and its transfer into the cytoplasm. Euchromatin contains most of the structural genes of an organism (seeCHROMOSOME).

References in periodicals archive ?
3A) an euchromatic nucleus and a cytoplasm containing rough endoplasmic reticulum, Golgi bodies, and mitochondria.
Both types of Bs seemed to be nonhomologous, the acrocentric type always forming, when in double dose, a chiasmate bivalent that co-oriented along with the autosomes in metaphase I, while both arms of the metacentric B paired and formed a chiasma between their euchromatic ends (White 1951b).
International Human Genome Consortium, "Finishing the Euchromatic Sequence of the Human Genome" (2004) 431 Nature 931.
See International Human Genome Sequencing Consortium, Finishing the Euchromatic Sequence of the Human Genome, 431 NATURE 931 (2004) (reporting the results of the project).
See International Human Genome Sequencing Consortium, 'Finishing the Euchromatic Sequence of the Human Genome' (2004) 431 Nature 931.
A peer review assessment of the research has already confirmed that the finished sequence now covers more than 99% of the euchromatic (or gene-containing) portion of the human genome and was sequenced to an accuracy of 99.
To describe the different C-banding patterns, three autosomal morphs, denoted A, B, and C, were recognized on the basis of previous reports (10,12) (Figure 2): A morph (a subterminal C-heterochromatic block is present at one chromosomal end; the other end is euchromatic or has a very small C-band); B morph (C-heterochromatic blocks are clearly present at both chromosomal ends); and C morph (the chromosome is totally euchromatic or has a very small C-band).
All of the chromosomes in the Arrhenatherum accessions examined were generally euchromatic, with most telomeres and secondary constrictions having C-bands.
For example, one of the seminal discoveries in molecular population genetics is that the level of nucleotide polymorphism across the euchromatic genome is correlated with recombination rate.
A gene catalogue of the euchromatic male-specific region of the horse Y chromosome: comparison with human and other mammals.