Chapter 10.ppt-BB

Organization of eukaryotic chromosomes a eukaryotic

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Unformatted text preview: tic Chromosomes A eukaryotic eukaryotic chromosome contains a long, linear DNA molecule molecule Three types of DNA Three sequences are required for chromosomal replication and segregation segregation Repetitive Sequences Sequence complexity refers to the number of times a particular base sequence appears in the genome sequence There are three main types of There repetitive sequences repetitive – – – Unique or non-repetitive Moderately repetitive Highly repetitive Renaturation studies - understanding genome complexity A renaturation study involves the following steps: – 1. Double-stranded DNA is broken into small pieces – 2. The pieces are “melted” into single strands by heat 2. treatment treatment – 3. The temperature is lowered, allowing the renaturation of 3. complementary DNA strands complementary The rate of renaturation of complementary DNA The The renaturation rate of a particular DNA sequence The depends on the concentration of its complementary partner partner – Highly repetitive DNA - the fastest to renature Highly – Unique sequences will be the slowest to renature The kinetics of renaturation Where – C= – C0 = – k2 = C/ C0 is the fraction of DNA that is still in single-stranded form after a given length of C/ time time quantitative information about the quantitative complexity of DNA sequences complexity Experiment Experiment – Human DNA was sheared into Human small pieces (~ 600 bp each) small – Subjected to heat – allowed to renature at a lower allowed temperature temperature The rates of renaturation can be The represented in a plot of C/C0 versus C0t C/C – This is known as the ___________ Called a “cot” curve Called Eukaryotic Chromatin Compaction Eukaryotic The compaction of linear DNA in eukaryotic chromosomes The involves interactions between DNA and various proteins Nucleosomes The repeating structural unit within The eukaryotic chromatin is the__________ eukaryotic It is composed of double-stranded DNA It wrapped around an octamer of ____________ ____________ – An octamer is composed two copies An each of four different histones each – 146 bp of DNA make 1.6...
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