chromosomes - bogari.netbogari.net/bogari/principle_files/7-chromosomes.pdf · chromosome • these...
TRANSCRIPT
![Page 1: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/1.jpg)
CHROMOSOMES
![Page 2: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/2.jpg)
CHROMOSOME• The chromosome comes from Greek
– Chroma = color
– Soma= body (the colored body)
• Chromosomes are act as factors which distinguished one species from another.
• Chromosomes are formed of DNA which is embedded in protein material
• Chromosomes are facilitate the transmission of all genetic information from one generation to another.
• Cytogenetics: the science which study chromosome and cell division.
![Page 3: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/3.jpg)
CHROMOSOME MORPHOLOGY
• Submicroscopic
– Chromosome made up of supercoils of DNA.
• Microscopic
– Chromosome consists of two chromatids or sister chromatids
– Join together by centromere
– Centromere divided the chromosome into short (p=petite) and long (q=grande).
– The tip of each chromosome arms in named telomere
![Page 4: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/4.jpg)
CHROMOSOME
• These sister chromatids can be seen to be joined at a primary constriction known as the centromere.
• Centromeres are responsible for the movement of chromosomes at cell division.
• The tip of each chromosome arm is known as the telomere.
• Telomeres play a crucial role in sealing the ends of chromosomes and maintaining their structural integrity.
![Page 5: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/5.jpg)
CENTROMERE
![Page 6: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/6.jpg)
TELOMERESThe end of each chromosome to ensure the genomic stability
Chromosome without telomeres
recombine with other chromatin, breakage, fusion,
and can loss.
Most cells being unable to undergo more than 50-60
divisions
increased telomerase activity has been implicated as a cause of abnormally prolonged cell survival
![Page 7: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/7.jpg)
CHROMOSOME MORPHOLOGY
![Page 8: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/8.jpg)
CHROMOSOME MORPHOLOGY
![Page 9: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/9.jpg)
CHROMOSOME MORPHOLOGY
![Page 10: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/10.jpg)
CHROMOSOME MORPHOLOGY
![Page 11: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/11.jpg)
CHROMOSOME MORPHOLOGY
![Page 12: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/12.jpg)
![Page 13: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/13.jpg)
![Page 14: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/14.jpg)
![Page 15: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/15.jpg)
CHROMOSOMAL CLASSIFICATION
The classification of chromosome is made according to three important parameters
• Length of chromosome
• Position of centromere
• Metacentric
• Submetacentric
• Acrocentric
![Page 16: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/16.jpg)
CHROMOSOMAL CLASSIFICATION
![Page 17: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/17.jpg)
CHROMOSOMAL CLASSIFICATION
• Presence or absence of satellite
• According to the above parameters: chromosomes are divided into 7 groups
• A= 1-3 B= 4-5 C=6-12+X D=13-15
• E=16-18 F=19-20 G=21-22+Y
![Page 18: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/18.jpg)
CHROMOSOMAL CLASSIFICATION
![Page 19: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/19.jpg)
![Page 20: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/20.jpg)
CHROMOSOME Made of DNA and
protein 23 pair Autosomes
– Pair 1-22 Sex chromosomes
– X and Y
![Page 21: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/21.jpg)
![Page 22: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/22.jpg)
CHROMOSOME
• In humans the normal cell nucleus contains 46 chromosomes, made up of 22 pairs of autosomes and a single pair of sex chromosomes - XX in the female and XY in the male.
• Each human cell (somatic cells) contains 46 chromosomes (diploid number of chromosomes) except mature gametes (sperms and ova) each cell contains 23 chromosomes (haploid number of chromosomes) i.e. 22 autosomes + one sex chromosome)
![Page 23: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/23.jpg)
HOMOLOGOUS PAIRS OF CHROMOSOMES
• Members of a pair of chromosome are known as homologues (carrying the same gene).
• Each chromosome has a certain gene on it.
• A homologous pair is a pair with the same gene one from mother, one from father.
![Page 24: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/24.jpg)
BANDING (STAINING) TECHNIQUES
• The development of chromosome banding (staining) enable very precise recognition of individual chromosomes and the detection of chromosome abnormalities
• The technique (staining) also revealed that chromatin, exists in two main forms.
– Euchromatin stains lightly and consists of genes which are actively expressed.
– Heterochromatin stains darkly and is made up largely of inactive unexpressed repetitive DNA.
![Page 25: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/25.jpg)
![Page 26: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/26.jpg)
PREPARATION OF KARYOTYPE
![Page 27: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/27.jpg)
G BANDING•Most common use•In the Metaphase
•chromosome treated with trypsin•Then stained with Giemsa
R band •Stain light•GC rich •have the highest gene density G bands •Stain dark •AT rich •have relatively fewer genes than R bands
![Page 28: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/28.jpg)
Q BANDING
•It is similar to that obtained with Giemsa •requires examination with ultraviolet fluorescent microscope
![Page 29: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/29.jpg)
R-banding
The chromosomes are heat-
denaturedthen staining with
Giemsa
![Page 30: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/30.jpg)
C-banding
•Chromosomes are pretreated with acid•followed by alkali •then Giemsa
![Page 31: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/31.jpg)
CHROMOSOME
![Page 32: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/32.jpg)
THE SEX CHROMOSOMES• In humans both the male and the female have two sex
chromosomes
-XX in the female and
– XY in the male.
• The Y chromosome is much smaller than the X chromosome.
• Genes on the Y chromosome include testis determining factor known as SRY gene.
• Other genes on the Y chromosome are known to be important in maintaining spermatogenesis.
![Page 33: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/33.jpg)
THE SEX CHROMOSOMES
• In the female each ovum carries an X chromosome.
• As there is a roughly equal chance of either an X-bearing sperm or a Y -bearing sperm fertilizing an ovum, the numbers of male and female conceptions are approximately equal.
• In fact slightly more male babies are born than females, although during childhood and adult life the sex ratio evens out at 1:1.
![Page 34: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/34.jpg)
![Page 35: CHROMOSOMES - bogari.netbogari.net/Bogari/Principle_files/7-Chromosomes.pdf · CHROMOSOME • These sister chromatids can be seen to be joined at a primary constriction known as the](https://reader031.vdocuments.us/reader031/viewer/2022020319/5cc68b2b88c99368098d18e1/html5/thumbnails/35.jpg)
PUNNETT`S SQUARE SHOWING SEX CHROMOSOME COMBINATIONS FOR
MALE AND FEMALE GAMETES