Chapter 5
DNA and Chromosome Structure
![DNA Packaging](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10785.jpg)
Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside the…
![DNA as a Genetic Template](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11527.jpg)
Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature.…
![Chromosome Structure](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11529.jpg)
A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA…
![Chromosome Replication](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11530.jpg)
Before a cell can divide, it must accurately replicate all of its chromosomes, including the DNA and its associated histone and non-histone…
![The Nucleosome Core Particle](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11532.jpg)
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies…
![Nucleosome Remodeling](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11533.jpg)
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA…
![Karyotyping](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10787.jpg)
Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated…
![Position-effect Variegation](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11536.jpg)
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and…
![Spreading of Chromatin Modifications](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11538.jpg)
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed…
![Lampbrush Chromosomes](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11539.jpg)
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined…
![Histone Variants at the Centromere](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11541.jpg)
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that…
![Inheritance of Chromatin Structures](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11542.jpg)
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the…
![Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes](https://cloudfront.jove.com/files/thumbs/51720_t.png)
INO80 chromatin remodeling complexes regulate nucleosome dynamics and DNA accessibility by catalyzing ATP-dependent nucleosome remodeling. Human…
![Chromatin Immunoprecipitation (ChIP) of Histone Modifications from <em>Saccharomyces cerevisiae</em>](https://cloudfront.jove.com/files/thumbs/57080_t.png)
Histone post-translational modifications (PTMs), such as acetylation, methylation and phosphorylation, are dynamically regulated by a series of…