Some DNA does not encode protein.
Long non-coding sequences separate relatively infrequent islands of genes in eukaryotic DNA.
In most cases when DNA is extracted from living cells, the proteins (including histones) are dissolved away. This results in long strands of naked DNA, which retain their genetic information. So it is useful to visualize a chromosome as a continuous strand of DNA. Arrayed along the DNA strand are the genes, specific regions whose sequences carry the genetic code for making specific proteins. The genes of bacteria are tightly packed together; virtually all the DNA encodes proteins. However, experiments done in the 1960s, showed that a large proportion of eukaryotic DNA is composed of repeated sequences that do not encode proteins. Long non-coding sequences â€” or intergenic regions â€” separate relatively infrequent "islands" of genes. Research in the 1970s showed that numerous non-coding sequences â€” introns â€” are also found within genes, interrupting the protein-coding regions, or exons. It is estimated that only about five percent of human DNA encodes protein.
genes, dna strand, naked dna, eukaryotic dna, intergenic regions, non-coding sequences, introns, exons, histones, genetic code, chromosome, sequences, proteins, bacteria
- ID: 16656
- Source: DNALC.DNAFTB
RNA splicing removes non-coding introns and splices together exons.
An animation shows how the DNA genetic "code" is made into protein.
An animation of the crucial RNA editing step called splicing.
In most eukaryotic genes, coding regions (exons) are interrupted by noncoding regions (introns).
Dr. Roberts describes the flow of information from DNA to RNA to protein.
Each chromosome is a package for one very long, continuous strand of DNA.
DNAFTB Animation 31: Roy Britten presents his work with David Kohne on repetitive DNA and its evolutionary origins.
Mike Wigler shows how all organisms share similar genes, called homologs.
Stanley Cohen and Herbert Boyer transform bacteria with a recombinant plasmid, and Doug Hanahan studies induced transformation.
Rich Roberts and Phil Sharp explain restriction enzymes, electrophoresis, and split genes.