Correct option is B
Explanation-
In Yeast — SIR Complex
The SIR (Silent Information Regulator) complex is crucial for heterochromatin formation in yeast. It is composed mainly of Sir2, Sir3, and Sir4, it regulates telomeric silencing, silent mating-type loci, and rDNA. Sir2 is also a histone deacetylase, helping condense chromatin and repress transcription.
In Humans — HP1 (Heterochromatin Protein 1)
HP1 binds to methylated histone H3 at lysine 9 (H3K9me3). It plays a key role in forming heterochromatin, maintaining nuclear architecture, and gene silencing. It’s a hallmark protein for constitutive heterochromatin in humans.
Incorrect options-
Option a – HP1 and SIR Complex → Order is incorrect.
Option c – HP1 and Su(var) → Su(var) is from Drosophila, not human.
Option d – SIR and Su(var) → Su(var) again isn’t human-specific.
So, the correct answer is option b - SIR complex and HP1
