Chromosome Evolution

Fissions and fusion is the most common way for the number of chromosomes to change.

Humans have 23 pairs of chromosomes, but all of the other great apes have 24 pairs. At some point since our lineage split from that of chimpanzees, two chromosomes fused

TLS Online TPP Program

#Id: 384

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 385

#Unit 2. Cellular Organization

H32-H42 tetramer accounts for the diameter of the octamer and H32-H42 tetramer alone can organize DNA in vitro into particles that display the properties of the core particle.

 

TLS Online TPP Program

#Id: 386

#Unit 2. Cellular Organization

The H32.H42 tetramer bound to DNA recruits two copies of the H2A.H2B dimer to complete the assembly of the final nucleosome

TLS Online TPP Program

#Id: 387

#Unit 2. Cellular Organization

The nucleosome has an approximate twofold axis of symmetry, called the dyad axis.

TLS Online TPP Program

#Id: 388

#Unit 2. Cellular Organization

DNA enters at 1 o’clock and exits at just short of 11 o’clock on one axis and they change time after 180 degree rotation

TLS Online TPP Program

#Id: 389

#Unit 2. Cellular Organization

The H3.H4 tetramers and H2A.H2B dimers each interact with a particular region of the DNA within the nucleosome can be shown by clock analogy.