A
Seminar on
CHROMOSOMES
Presented
By

K. GANAPATHI RAO
(13031D6003)
Presence of
Miss. CH SILPA CHAKRA
(HOD) CNST-JNTUH IS...
OUTLINE
•
•
•
•
•
•
•
•

Introduction.
Chromosome.
Types Of Chromosomes.
Cell Division.
Meiosis And Fertilisation.
Human C...
CELL
• Basic unit of building the body
Chromosomes In Different Cells
PROKARYOTES

EUKARYOTES

single chromosome plus plasmids

many chromosomes

circular chromo...
Chromosome
• Chromosomes are the rod-shaped, filamentous bodies
present in the nucleus, which become visible during cell
d...
CHROMOSOME
NUCLEOSOMES

30 NM SOLENOID/
CHROMATIN FIBER
CHROMATIN FIBER
LOOPS
No of chromosomes
• Normally, all the individuals of a species have
the same number of chromosomes.
• Presence of a whole ...
No of chromosomes
Round worm
Onion
Tomato

2
16
24
Chromosome Size
In contrast to other cell organelles, the size of chromosomes shows
a remarkable variation depending upon ...
Can distinguish chromosomes by “painting” – using DNA
hybridization + fluorescent probes
Types of Chromosomes
• Autosomes

– Paired chromosomes with the same length, shape,
centromere location, and genes
– Any c...
CELL DIVISIONS
• Meiosis:
–
–
–
–

A special type of cell division
Used to make sex cells
Meiosis halves the numbers of ch...
Meiosis and fertilisation
Mother

Father

23 pairs of
chromosomes

23 pairs of
chromosomes

Meiosis

23 unpaired
chromosom...
The inheritance of gender

Is it going to be a boy or a girl?
The inheritance of gender
Mother

Father

XX

XY

X

X

X

X
Fertilisation

Y

X

XX

XY

X

XX

XY

Y

Possible
children
...
Human chromosomal abnormalities
Numerical (Chromosomal Disorders)
•
•
•
•

Trisomy = 3 copies of a single chromosome 47
Mo...
Causes of Chromosomal Disorders
• Ionising radiation, autoimmunity, virus infections and
chemical toxins in the pathogenes...
Some Numerical Disorders
 XXY = Klinefelter’s syndrome male
 Feminine character.
 Tall, Normal Intelligence.

 XXX = T...
Chromosomes Structure
–
–
–
–

Centromere
p arm
q arm
Telomeres
Arm

Region

2

p
1

1

Band

2
1
1

1

q
3

Chromosome 17

3
2
1
2
1
5
4
3
2
1
1
2

2

2

Subband

4

3
1
2
3
1
2, 3
4
1
...
Chromosome Structure Abnormalities

Translocation

Deletion

Derivative
chromosome

Inversion

Insertion

Isochromosome

R...
Some Structural Disorders
• Cri-Du-Chat Syndrome
–
–
–
–

#5q Deletion
Moon-shaped face, Heart disease
Mentally retarded, ...
Some Structural Disorders
• Prader-Willi Syndrome
–
–
–
–

#15q Deletion
Small bird-like head, Mentally retarded
Respirato...
Some Structural Disorders
• Cat-Eye Syndrome
–
–
–
–

#22q Deletion
Fused fingers and toes
Mentally retarded, Small jaw
He...
Videos
1. What Is A Chromosome.
2. How Dna Is Packaged (Advanced).
3. Chromosome Disorder Outreach Video.
4. Unique Childr...
REFRENCE
• Human Chromosomes by Orlando J. Miller,
• Chromosome biology by R. Appels,
• http://www.chromodisorder.org/CDO/...
Chromosomes
Chromosomes
Chromosomes
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  • Their number can be counted easily only during mitotic metaphase.
  • Chromosomes

    1. 1. A Seminar on CHROMOSOMES Presented By K. GANAPATHI RAO (13031D6003) Presence of Miss. CH SILPA CHAKRA (HOD) CNST-JNTUH IST
    2. 2. OUTLINE • • • • • • • • Introduction. Chromosome. Types Of Chromosomes. Cell Division. Meiosis And Fertilisation. Human Chromosomal Abnormalities. Chromosomes Structure. Structural Chromosomes Disorders.
    3. 3. CELL • Basic unit of building the body
    4. 4. Chromosomes In Different Cells PROKARYOTES EUKARYOTES single chromosome plus plasmids many chromosomes circular chromosome linear chromosomes made only of DNA made of chromatin, a nucleoprotein (DNA coiled around histone proteins) found in cytoplasm found in a nucleus copies its chromosome and divides copies chromosomes, then the cell immediately afterwards grows, then goes through mitosis to organise chromosomes in two equal groups
    5. 5. Chromosome • Chromosomes are the rod-shaped, filamentous bodies present in the nucleus, which become visible during cell division. • They are the carriers of the gene or unit of heredity. • Chromosome are not visible in active nucleus due to their high water content, but are clearly seen during cell division. • Chromosomes were first described by Strausberger in 1875. • The term “Chromosome”, however was first used by Waldeyer in 1888. Chromo=colour Soma=body Chromosome
    6. 6. CHROMOSOME
    7. 7. NUCLEOSOMES 30 NM SOLENOID/ CHROMATIN FIBER CHROMATIN FIBER LOOPS
    8. 8. No of chromosomes • Normally, all the individuals of a species have the same number of chromosomes. • Presence of a whole sets of chromosomes is called euploidy. • When a change in the chromosome number does not involve entire sets of chromosomes, but only a few of the chromosomes - is Aneuploidy. • Gametes normally contain only one set of chromosome – this number is called Haploid • Somatic cells usually contain two sets of chromosome – 2n - Diploid – 3n – triploid – 4n – tetraploid
    9. 9. No of chromosomes Round worm Onion Tomato 2 16 24
    10. 10. Chromosome Size In contrast to other cell organelles, the size of chromosomes shows a remarkable variation depending upon the stages of cell division. • Interphase: chromosome are longest & thinnest • Prophase: there is a progressive decrease in their length accompanied with an increase in thickness • Anaphase: chromosomes are smallest. • Metaphase: Chromosomes are the most easily observed and studied during metaphase when they are very thick, quite short and well spread in the cell.
    11. 11. Can distinguish chromosomes by “painting” – using DNA hybridization + fluorescent probes
    12. 12. Types of Chromosomes • Autosomes – Paired chromosomes with the same length, shape, centromere location, and genes – Any chromosome other than a sex chromosome – Determine size, colour, hair of a body. • Sex chromosomes – Members of a pair of chromosomes that differ between males and females HOMOGAMETIC SEX HETEROGAMETIC SEX SEX DETERMINATION Female XX Male XY Presence of Y-chromosome = maleness (mammals and fish) Presence of second X-chromosome = femaleness (Drosophila, the fruit fly) Male ZZ Female ZW Birds, amphibians, reptiles, butterflies, moths. Female XX Male Xo Grasshoppers
    13. 13. CELL DIVISIONS • Meiosis: – – – – A special type of cell division Used to make sex cells Meiosis halves the numbers of chromosomes Meiosis picks one chromosome from each pair at random and places them in a sex cell. This results in enormous variation amongst the sex cells • Mitosis: – Normal cell division – Chromosomes are duplicated and distributed equally
    14. 14. Meiosis and fertilisation Mother Father 23 pairs of chromosomes 23 pairs of chromosomes Meiosis 23 unpaired chromosomes 23 unpaired chromosomes 23 unpaired chromosomes Fertilisation 23 pairs of chromosomes Child 23 unpaired chromosomes
    15. 15. The inheritance of gender Is it going to be a boy or a girl?
    16. 16. The inheritance of gender Mother Father XX XY X X X X Fertilisation Y X XX XY X XX XY Y Possible children Chance of a girl 50% Chance of a boy 50%
    17. 17. Human chromosomal abnormalities Numerical (Chromosomal Disorders) • • • • Trisomy = 3 copies of a single chromosome 47 Monosomy = 1 copy of a single chromosome 45 Triploidy = 3N Tetraploidy = 4N Structural (Chromosomal Disorders) – Deletion – Duplication – Translocation (involves 2 chromosomes)
    18. 18. Causes of Chromosomal Disorders • Ionising radiation, autoimmunity, virus infections and chemical toxins in the pathogenesis of certain disorders.
    19. 19. Some Numerical Disorders  XXY = Klinefelter’s syndrome male  Feminine character.  Tall, Normal Intelligence.  XXX = Trisomy X female  Produce healthy female.  XYY = Jacob’s syndrome male  Height, more active.  Slightly learning disability.  Normal intelligence.  X/XO = Turner syndrome female • Webbed neck. • Short height. • Immature females.
    20. 20. Chromosomes Structure – – – – Centromere p arm q arm Telomeres
    21. 21. Arm Region 2 p 1 1 Band 2 1 1 1 q 3 Chromosome 17 3 2 1 2 1 5 4 3 2 1 1 2 2 2 Subband 4 3 1 2 3 1 2, 3 4 1 2 3 17 q 1 1 . 2
    22. 22. Chromosome Structure Abnormalities Translocation Deletion Derivative chromosome Inversion Insertion Isochromosome Ring chromosome
    23. 23. Some Structural Disorders • Cri-Du-Chat Syndrome – – – – #5q Deletion Moon-shaped face, Heart disease Mentally retarded, Malformed larynx Normal lifespan • Aniridia-Wilms Tumor Syndrome – – – – #11p Deletion Mentally retarded, Growth retarded Blindness, Tumors on kidneys Short lifespan • Thirteen Q Deletion Syndrome – Mentally retarded, Deformed face – No thumbs, Heart disease – Short lifespan
    24. 24. Some Structural Disorders • Prader-Willi Syndrome – – – – #15q Deletion Small bird-like head, Mentally retarded Respiratory problems Obesity, Short lifespan • Eighteen Q Deletion Syndrome – – – – – #18q Deletion Mentally retarded, Heart disease Abnormal hands and feet Large eyes, Large ears Normal lifespan • Burkitt Lymphoma – Translocation of the Myc gene on chromosome 8 – Translocated Myc genes don’t function properly – Leads to cancer of the lymph nodes
    25. 25. Some Structural Disorders • Cat-Eye Syndrome – – – – #22q Deletion Fused fingers and toes Mentally retarded, Small jaw Heart problems, Normal lifespan • Patau’s Trisomy Syndrome – – – – – – #13 Trisomy Nondisjunction Small head, Small or missing eyes Heart defects, Extra fingers Abnormal genitalia, Mentally retarded, Cleft palate Most die a few weeks after birth • Four-Ring Syndrome – – – – #4 Inversion Cleft palate, Club feet Testes don’t descend Short lifespan
    26. 26. Videos 1. What Is A Chromosome. 2. How Dna Is Packaged (Advanced). 3. Chromosome Disorder Outreach Video. 4. Unique Children With Rare Chromosome Disorders.
    27. 27. REFRENCE • Human Chromosomes by Orlando J. Miller, • Chromosome biology by R. Appels, • http://www.chromodisorder.org/CDO/ • http://www.genome.gov/26524120 • http://www.youtube.com/watch?v=zf7tbymrv9 o • http://www.johnkyrk.com/chromosomestructu re.html
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