heterochromatinchromosomefullchapterppt.pdf

Heterochromatin seminar submitted by Nandita vyas uder taken Dr. Sunita Arora, department of botany Jai Narain Vyas University jodhpur ..

1. JAI NARAIN VYAS UNIVERSITY JODHPUR
Department of botany
DCC –BOT 8022T
Topic –Heterochormatin
Submitted to : submitted by:
Dr. SunitaArora nanditaVyas

2. Content
•Chromatin
•Euchromatinand heterochromatin
•Heterochromatin
•Constitutive heterochromatin
•Facultative heterochromatin

3. Chromatin
•Chromatin is an Organized structure Of DNA and
protein That are found In nucleus of eukaryotic
cell.
•When chromosome are stain by various
procedure such as FeulgenOr acetocarminThey
differentiate into 2 region –
1.Euchromatin(light stain )
2.Heterochromatin (dark stain )

7. HETEROCHROMATIN
•Heterochromatin Is dark stain region Of chromatin
that remain condensed.
•The chromatin fiber in this region are more tightly
folded.
•They are transcriptionally inactive
•In hetero chromatin the DNA is tightly packed in
the 30 nm fiber

8. •Present at periphery of nucleus .
•Found only in eukaryotes.
•There are 2 type of heterochromatin ,
constitutive and facultative heterochromatin
•Both the hetero chromatin Play role In
Expression of genes .
.

9. Constitutive hetero chromatin
•In constitutive heterochromatin , the DNA is
permanently inactive and remain in the
Condensed state Throughout the life .
•It is found In telomere and centromere It is also
contain Short repeated sequence of DNA called
Satellite DNA .
•Replicate late in s-phase

10. Facultative heterochromatin
•When Euchromatinis converted into
heterochromatin it is called facultative
heterochromatin . This process is know as
Euchromatinization.
•Eg. X chromosome inactivation in female
mammals. In this case one x chromosome
become facultative while other x chromosome
remain Euchromatinand is expressed.

12. Reference –
•Cytology and genetic by p.k. Gupta
•Cell biology by s.chand

13. Thank
You