MCB 150 Lecture Notes - Lecture 19: Ribonucleoprotein, Tandemly Arrayed Genes, A Reminder
7 Dec 2017
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In 1885, carl rabl proposed that each chromosome occupies a distinct territory. In 1984, the rabl model of chromosome organization was confirmed by detailed studies of polytene chromosomes (replicate but don"t separate) in drosophila. Hundreds or even thousands of identical copies of the dna molecule still stuck together. Fluorescence can be used to visualize and identify chromosomes: Probe molecule single strand nucleic acid with dye detectable form complementary bp dye for particular dna sequence label the probe two copies of the chromosome. Replicated but not yet separated 4 bright green dots. Chromosome painting can help us visualize chromosomal domains: Panel a: chicken chromosome spread during mitosis, stained with a general dna stain. Panel b: the same chromosome spread stained with unique paints for each chromosome (macro-chromosomes) Each chromosome occupies a distinct territory within the nucleus arranged in an organized fashion. Nuclei are divided into discrete functional domains that play an important role in regulating gene expression and in replication.
