Chromosomal Abrration pptx by Rutuja Mane

Chromosomal Abrration

1. Chromosomal Aberration By Ms. Rutuja Mane Bsc nursing solapur

2. Introduction Chromosomal aberrations refer to changes in the normal structure or number of chromosomes within an organism's cells, These changes can lead to genetic Disorders or diseases by affecting gene expression, disrupting genetic information, or altering genetic pathways. Chromosomal aberrations can occur during cell division when chromosomes are duplicated & distributed into daughter cells

3. Types Numerical Structural

4. Numerical aberrations This involves a change in the number of chromosomes. These can occur through nondisjunction (failure of chromosomes to separate properly during cell division), leading to aneuploidy (an organism has one chromosome more or less than the normal set) or polyploidy ( more than two complete Sets of chromosomes)

5. Aneuploidy Examples include Down syndrome (trisomy 21, an extra chromosome21), Turner syndrome (monosomy X, a single X chromosome in females)

6. Polyploidy Common in plants and some animal species, resulting in organisms with more than two sets of chromosomes.

7. Structural Aberrations These involve changes in the structure of chromosomes. They can result from breaks in chromosomes that lead to loss, rearrangement, or duplication of chromosome segments. Types of structural aberrations include: Deletions: A segment of a chromosome is missing or deleted. Duplications: A segment of a chromosome is duplicated, leading to extra genetic material.

8. Types of structural aberrations conti…. Inversions: A chromosome segment breaks off, flips around, and reattaches, so the genetic material is in reverse order. Translocations: Segments from two different chromosomes swap places or a segment moves from one chromosome to another, potentially disrupting gene function.

9. Numerical Chromosomal Aberrations Normal cells are diploid containing 46 chromosomes, 22 pairs of autosomes and 1 pair of sex chromosomes. The total number of chromosomes may be either increased or deceased The deviation from the normal number of chromosomes is called as numerical chromosomal aberrations and are classified into two main subtypes: Euploid & Aneuploid

10. Euploid Euploidy refers to cells having exact multiples of the haploid number of chromosomes, other than the typical diploid number. Triploid (3n): C ells contain three sets of chromosomes. This is more than the usual two sets found in most human cells, resulting in a total of 69 chromosomes. Tetraploid (4n): C ells have four sets of chromosomes, doubling the normal diploid number, making up 92 chromosomes

11. Polyploidy :- A general term for cells with more than two sets of chromosomes . This can include triploid, tetraploid, and higher multiples. Polyploidy is common in plants but usually results in severe developmental problems or miscarriage in humans.

12. Aneuploidy Aneuploidy occurs when the number of chromosomes is not an exact multiple of the haploid set, leading to an imbalance in genetic material. Monosomy: The loss of a single chromosome from the normal set, resulting in 45 chromosomes instead of the usual 46. An example is Turner syndrome (45.X), where there is only one X chromosome. Trisomy : The addition of an extra chromosome to the normal set, leading to 47 chromosomes in total. Examples include Down syndrome (Trisomy 21)

13. Tetrasomy: The presence of two extra chromosomes in the normal set, resulting in 48 chromosomes. This is less common and can lead to various genetic conditions, depending on which chromosomes are duplicated.

14. Structural Chromosomal Aberrations Structural aberrations are changes in the structure of chromosomes. These alterations can affect the physical appearance of chromosomes and lead to various genetic disorders. The Structural aberrations are classified into several subtypes based on the nature

15. Deletion :- Occurs when a segment of a chromosome is lost, leading to a chromosome with missing genes. Terminal Deletion: A segment from the end of a chromosome is lost. Intercalary Deletion : A segment from the middle of a chromosome is lost, with the two remaining parts then reconnecting.

16. Duplication Duplication involves the repetition of a chromosome segment, increasing the number of copies of genes in that segment. Terminal Duplication: A segment at the end of a chromosome is duplicated. Intercalary Duplication: A segment in the middle of a chromosome is duplicated.

17. Inversion An inversion occurs when a chromosome segment breaks off, flips around, and reattaches in the opposite orientation. Pericentric Inversion: The inversion includes the centromere, changing the position of the centromere and the sequence of genes. Paracentric Inversion: The inversion occurs outside of the centromere, not affecting the position of the centromere but altering the gene sequence.

18. Translocations Translocation is when a segment of one chromosome detaches and reattaches to a different chromosome. Reciprocal Translocation: S egments from two different chromosomes swap places with each other without any loss of genetic material. Robertsonian:- This involves the fusion of two acrocentric chromosomes at their centromeres, forming a single chromosome and often leading to a reduction in the total number chromosomes