Plegable BIOLOGÍA MOLECULAR. Cromosomas, cromatina y ciclo celular.

2. • University of Massachusetts
Medical School. (2016, July 21).
Scientists untangle Barr body
of inactive X chromosome:
Highly elaborate chromosome
structure. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releas
es/2016/07/160721143503.htm
• Asociación RUVID. (2016, July
20). XX protection against age-
related
mutations. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releas
es/2016/07/160720094446.htm
• MARTINEZ SÁNCHEZ, Lina
María. Biología molecular. 8.
ed. Medellín: UPB. Fac. de
Medicina, 2015. 59 p.
• University of Massachusetts
Medical School. (2016, July 21).
Scientists untangle Barr body
of inactive X chromosome:
Highly elaborate chromosome
structure. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releas
es/2016/07/160721143503.htm
• Asociación RUVID. (2016, July
20). XX protection against age-
related
mutations. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releas
es/2016/07/160720094446.htm
• MARTINEZ SÁNCHEZ, Lina
María. Biología molecular. 8.
ed. Medellín: UPB. Fac. de
Medicina, 2015. 59 p.
The researches treated in
here have special
importance because they
decrypt chromosomal
machinery by giving a
description of the Barr body
that involves active DNA
and by describing that an
inactive X chromosome has
a protective effect for
females. This may be the
answer ofor sex prevalence
diseases and aging process
in genders and this is the
point where genic therapy
can make tracking of
specific mutations and give
a diagnosis or cure in
agreement to specific
genes and its expression.
The researches treated in
here have special
importance because they
decrypt chromosomal
machinery by giving a
description of the Barr body
that involves active DNA
and by describing that an
inactive X chromosome has
a protective effect for
females. This may be the
answer ofor sex prevalence
diseases and aging process
in genders and this is the
point where genic therapy
can make tracking of
specific mutations and give
a diagnosis or cure in
agreement to specific
genes and its expression.

3. The chromatin is a condensed
structured formed by
eukaryotic DNA and chromatin
proteins like histones and non-
histone proteins.
A chromosome is a structure
composed by wrapped
chromatin and it is essential for
the cellular division.
Cell cycle is the process that
cells make to divide and origin
daughter cells with an specific
amount of genetic information
and it’s divided in three periods
called interphase, mitosis and
cytokinesis.
All these events are involved in
organism maintenance and
development.
The chromatin is a condensed
structured formed by
eukaryotic DNA and chromatin
proteins like histones and non-
histone proteins.
A chromosome is a structure
composed by wrapped
chromatin and it is essential for
the cellular division.
Cell cycle is the process that
cells make to divide and origin
daughter cells with an specific
amount of genetic information
and it’s divided in three periods
called interphase, mitosis and
cytokinesis.
All these events are involved in
organism maintenance and
development.
Researchers at the University of
Valencia's Cavanilles Institute of
Biodiversity and Evolutionary
Biology tested and confirmed
that differences in lifespan
between the sexes may indeed
be due to the protective effect
of having two copies of the X
chromosome.
The explanation for this lies in the
fact that most genetic
mutations are by nature
recessive. For XX individuals, this
means they are only harmful
when the same mutation occurs
in both copies of the X
chromosome, otherwise they
are not expressed. In the case of
XY individuals, with no 'guard',
any recessive mutation present
in either the X or the Y
chromosome would be
expressed unconditionally.
STUDENT’S OBSERVATION
This study helps to develop a full
explanation about mutational
expression and aging in males,
being an important target for
genic therapy.
Researchers at the University of
Valencia's Cavanilles Institute of
Biodiversity and Evolutionary
Biology tested and confirmed
that differences in lifespan
between the sexes may indeed
be due to the protective effect
of having two copies of the X
chromosome.
The explanation for this lies in the
fact that most genetic
mutations are by nature
recessive. For XX individuals, this
means they are only harmful
when the same mutation occurs
in both copies of the X
chromosome, otherwise they
are not expressed. In the case of
XY individuals, with no 'guard',
any recessive mutation present
in either the X or the Y
chromosome would be
expressed unconditionally.
STUDENT’S OBSERVATION
This study helps to develop a full
explanation about mutational
expression and aging in males,
being an important target for
genic therapy.
Scientist at UMass Medical School,
the Institut Curie in Paris and
Stanford University have taken a
detailed look inside the small,
densely packed structure of the
inactive X chromosome found in
female mammals called the Barr
body.
What they found was that the Barr
body wasn't a single dense mass
of DNA but instead is composed
of two separately packed lobes
separated by a highly repetitive
segment of DNA called a
macrosatellite repeat, found only
in a few places in the genome. Dr.
Dekker speculates that these
macrosatellite repeats are
responsible for packing and
organizing DNA inside the Barr
body.
STUDENT’S OBSERVATION
Finding a possible function of the
Barr body can open doors to
research in the field of mutations
in DNA packing and relate it to
female prevalence diseases giving
the key to a cure.

4. Chromatin packaged in
chromosomes allows genetic
information to fit in the nucleus
Determines the characteristics of
every cell of the organism
Growth, development, division,
gametes origin and preservation
of genetic information are in
charge of cell cycle

5. Scientists untangle Barr body of inactive X
chromosome: Highly elaborate
chromosome structure.
University of Massachusetts Medical.
21 July 2016.

6. Inactive X chromosome:
highly organized structure
 Two distinct lobes of
condensed inactive DNA
 Smaller structured
domains of active DNA
embedded in them
Domains  significant role in
gene expression
The Barr body is composed
of two separately packed
lobes separated by a
highly repetitive segment
of DNA called a
MACROSATELLITE REPEAT
Responsible for packing
and organizing DNA inside
the Barr body?

7. Process of the
three-dimensional
structure of the
chromosomes
Process of the
three-dimensional
structure of the
chromosomes
Cross two different mouse
strains
Build a computational approach
Use naturally occurring mutations in one
of the X chromosomes as guideposts
Fill in the gaps
computationally and
connect enough dots

8. Clusters of genes inside
the lobes that are being
expressed
These genes reside inside
topologically associating
domains (TADs)
TADs organize the
genome into
neighborhoods separated
by boundaries rich in
CTCF proteins
CTCF proteins repress
transcription
TADs play a role in
making organizing
gene expression

10. XX protection against age-related
mutations.
Asociación RUVID.
20 July 2016.

11. “The accumulation of
mutations over the course of
a lifetime, or passed on from
generation to generation,
has a larger affect on the sex
that has just one 'unguarded'
copy of the X chromosome;
generally males, including in
human beings.”

12. Affects the lifespan of the
homogametic sex (individuals
with two of the same sex-
determining chromosomes)
to a greater extent
INBREEDING in
Drosophila
melanogaster
Heterogametic sex (with two
different sex-determining
chromosomes)is less affected
The X chromosome is only 'guarded' if the
two X chromosomes are different, which
is not the case after repeated inbreeding
The X chromosome is always
'unguarded', with or without
inbreeding

13. Otherwise they
are simply not
expressed
XX individuals: they
are only harmful when
the same mutation
occurs in both copies
of the X chromosome
Most genetic
mutations are
by nature
recessive

16. Full development of
the chromosome
structure is important
for people of the
medical field to
understand its function
and so, gen expression
applied to health or
pathology.

17. This researches may be the
explanation of why some mutations
affect males over females and that
enables the development of specific
treatments to prevent or to cure the
diseases caused by them.

18. Both studies were made with the
final intention of increasing general
people’s life quality by
understanding normal genetic
expression and abnormalities that
are the cause of many diseases or
the prone to it. An specific
chromosome and an specific
location may be applied by genic
therapy according to everyone’s
differences. By using this resource in
the medical field patients would
have much better results.
Both studies were made with the
final intention of increasing general
people’s life quality by
understanding normal genetic
expression and abnormalities that
are the cause of many diseases or
the prone to it. An specific
chromosome and an specific
location may be applied by genic
therapy according to everyone’s
differences. By using this resource in
the medical field patients would
have much better results.

19.  University of Massachusetts Medical School. (2016, July 21).
Scientists untangle Barr body of inactive X chromosome:
Highly elaborate chromosome structure. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releases/2016/07/160721143503.htm
 Asociación RUVID. (2016, July 20). XX protection against
age-related mutations. ScienceDaily. Retrieved July 28, 2016
from
www.sciencedaily.com/releases/2016/07/160720094446.htm
 MARTINEZ SÁNCHEZ, Lina María. Biología molecular. 8. ed.
Medellín: UPB. Fac. de Medicina, 2015. 59 p.
 University of Massachusetts Medical School. (2016, July 21).
Scientists untangle Barr body of inactive X chromosome:
Highly elaborate chromosome structure. ScienceDaily.
Retrieved July 27, 2016 from
www.sciencedaily.com/releases/2016/07/160721143503.htm
 Asociación RUVID. (2016, July 20). XX protection against
age-related mutations. ScienceDaily. Retrieved July 28, 2016
from
www.sciencedaily.com/releases/2016/07/160720094446.htm
 MARTINEZ SÁNCHEZ, Lina María. Biología molecular. 8. ed.
Medellín: UPB. Fac. de Medicina, 2015. 59 p.