Genetic drift 

Genetic drift is an evolutionary force, in which allelic frequency change over generation Just by chance (sampling error). 

The deviations from the expected ratios are random, the direction of change is unpredictable.

TLS Online TPP Program

#Id: 424

#Unit 2. Cellular Organization

30 nm compacts the DNA 40-fold. This structure of this fiber requires the histone tails and is stabilized by linker histones.

TLS Online TPP Program

#Id: 425

#Unit 2. Cellular Organization

This 30-nm fiber is further folded, results in 1000-fold compaction in euchromatin in interphase chromatin and in mitotic chromosomes to achieve an overall 10,000- fold compaction in euchromatin.

TLS Online TPP Program

#Id: 426

#Unit 2. Cellular Organization

Heterochromatin generally maintains 10,000-fold compaction in both interphase and mitosis after 30 nm.

TLS Online TPP Program

#Id: 427

#Unit 2. Cellular Organization

Chromatin contains DNA, Histones, Nonhistone Proteins and RNA. RNA polymerase is a prominent nonhistone protein

TLS Online TPP Program

#Id: 428

#Unit 2. Cellular Organization

Individual nucleosomes can be obtained by treating chromatin with the endonuclease micrococcal nuclease (MNase), which cuts the DNA between nucleosomes, a region known as linker DNA.

TLS Online TPP Program

#Id: 429

#Unit 2. Cellular Organization

Mononucleosomes typically have 200 bp DNA. End-trimming reduces the length of DNA first to 165 bp and then generates core particles with 146 bp.