STUCTURAL ANOMALIES OF CHROMOSOMES.pptx

ppt on genetics if structural anomalities of chromosomes

1. STUCTURAL ANOMALIES OF CHROMOSOMES NAME – YUG H. PUROHIT ROLL NO.- 149

2. INDEX INRODUCTION CLASSIFICATION FACTORS AFFECTING STRUCTURAL ABBERATION SUBSEQUENT TYPES OF STRUCTURAL ABBERATIONS CONCLUSION

3. INRODUCTION CHROMOSOMAL ABBERATION IS CHROMOSOMAL ABNORMALITY THAT INVOLVES MISSING,EXTRA OR IRREGULAR PORTION OF CHROMOSOME. STUDIED THROUGH- KARYOTYPE [FULL SET OF CHROMOSOMES FROM A PATIENT ] ABNORMAL CHROMOSOMAL THUS PRODUCES INHERITED ABNORMALITIES.

4. CLASSIFICATION CHROMOSOMAL ABBERATION ARE MAINLY CLASSIFIED INTO 2 TYPES : STUCTURAL ABBERATION NUMERICAL ABBERATION

5. FACTORS CAUSING ABBERATION ADVANCED MATERNAL AGE RADIATION PARENTAL CHROMOSOMAL ABBERATION AUTOIMMUNE DISORDER NUTRITIONAL DEFICIENCES [ FOLIC ACID ] ALCOHOL,TOBACCO, DRUG EXPOSURE INFECTION [ VIRUSES AND BACTERIA]

6. STUCTURAL ABBERATION WHEN CHROMOSOME STRUCTURE IS ATLERED IT PRODUCES STRUCTURE ABBERATION. MAY BE STABLE OR UNSTABLE. CLASSIFICATION DELETION TRANSLOCATION INSERTION INVERSION ISOCHROMOSOME RING CHROMOSOME DUPLICATION

7. DELETION 1. TERMINAL DELETION : TERMINAL SEGMENT IS LOST. EG.- cri-du-chat syndrome [ chromosome 5] 2. INTERSTITIAL DELETION : SEGMENT OF CHROMOSOME BETWEEN 2 BREAKS IS LOST. EG.- prader-willi syndrome [chromosome 15] 3. MICRODELETION : SMALL SEGMENT DELETION BUT LESS THAN 5 MILLION BP EG. –William syndrome

8. TRANSLOCATION OCCURS WHEN CHROMOSOMES BREAK AND JOIN TO ANOTHER NON HOMOLOGOUS CHROMOSOME. 2 TYPES : ROBERTISON : BREAK AT CENTROMERE AND FUSION WITH LOSS OF ACROCENTRIC SEGMENTS. EG.- CHROMOSOME 13 AND 14 [ 1 IN 1000 PEOPLE ] CHROMOSOME 21 [ DOWN SYNDROME ] RECIPROCAL : EXCHANGE OF MATERIAL BETWEEN 2 NON HOMOLOGOUS CHROMOSOMES. NO LOSS OF CHROMOSOMAL MATERIAL. ABNORMAL GAMETE PRODUCTION. EG.- PHILADELPHIA SYNDROME [ CHROMOSOME 22 AND 9 ]

9. INSERTION TRANSPOSITION OF SEGMENT OF ONE CHROMOSOME TO ANOTHER CHROMOSOME.

10. INVERSION TAKES PLACE WHEN THERE ARE 2 BREAKS IN A SINGLE CHROMOSOME AND THE SEGMENT TURNS 180* BEFORE REUNION. 2 TYPES: PERICENTRIC : BREAKS IN THE SHORT AND LONG ARM OF CHROMOSOME , THE SEGMENT ROTATES AROUND CENTROMERE . PARACENTRIC : BREAKS IN THE SAME ARM OF CHROMOSOME , SEGMENTS ROTATE AND FUSES.

11. ISOCHROMOSOME TRANSVERSAE DIVISION OF CENTROMERE – FUSION OF SHORT ARMS WITH EACH OTHER AND FUSION OF LONG ARMS. IN DERIVED ONES THEY ARE MIRROR IMAGES OF EACH OTHER. RING CHROMOSOME 2 BREAKS IN CHROMOSOMAL ENDS AND FUSION OF THE STICKY ENDS AND LOSS OF THE DISTAL MATERIAL. EG.- RING X PRODUCES TURNER SYNDROME.

12. DUPLICATION INVOLVES THE PRESENCE OF PORTION OF CHROMOSOME MORE THAN ONCE OR TWICE IN A ZYGOTE.

13. CONCLUSION CHROMOSOMAL ABBERATIONS ARE THE STRUCTION CHANGES IN STRUCTURES OF THE CHROMOSOME EITHER ONE OR TWO LEADING TO FURTHER CONSEQUES. AS MANY AS THE GENES INVOLVED FOR THE RESPECTIVE CHROMOSOMES , MUCH ARE THE SYMPTOMS SEEN.

14. THANK YOU ……..