Duplicate gene and its parental copy can subfunctionalize so that each carries out only some of the roles that the ancestral gene performed. 

Ex- a duplicate of the β-hemoglobin locus is expressed in the fetus. 

TLS Online TPP Program

#Id: 398

#Unit 2. Cellular Organization

Modification of histones is associated with replication and transcription, and specific modifications also facilitate DNA repair.

TLS Online TPP Program

#Id: 399

#Unit 2. Cellular Organization

Variants have been identified for all core histones except histone H4.

TLS Online TPP Program

#Id: 400

#Unit 2. Cellular Organization

MacroH2A is nearly three times larger than conventional H2A, and contains a large C-terminal tail that is not related to any other histone.

TLS Online TPP Program

#Id: 401

#Unit 2. Cellular Organization

Canonical H3 also known as H3.1 differs from the H3.3 variant at only four amino acid positions—three in the histone core and one in the N-terminal tail.

TLS Online TPP Program

#Id: 402

#Unit 2. Cellular Organization

Centromeric H3 (or CenH3) histone, known as Cse4 in yeast. CenH3 histones are incorporated into specialized nucleosomes present at centromeres.

TLS Online TPP Program

#Id: 403

#Unit 2. Cellular Organization

CenH3 has a unique N terminus, which does not resemble other core histones.