CHANGE IN STRUCTURE OF CHROMOSOMES

SY, Claire Darren L.

ROPAL, Roravelle N.

AAPD-2B

4 TYPES OF CHROMOSOMAL MUTATIONS

1. Deletion2. Duplication3. Inversion4. Translocation

DELETION Is also called gene

deletion, deficiency, or deletion mutation.

Is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is missing.

2 KINDS OF DELETION:

1. Terminal Deletion2. Intercalary Deletion /

Interstitial Deletion

TERMINAL DELETION

a deletion that occurs towards the end of a chromosome.

INTERCALARY DELETION / INTERSTITIAL DELETION

a deletion that occurs from the interior of a chromosome.

DUPLICATION or chromosomal

duplication or gene amplification.

is any duplication of a region of DNA that contains a gene.

4 KINDS OF DUPLICATION

1. Tandem2. Reverse tandem3. Displaced homobrachial4. Displaced heterobrachial

TANDEM

The occurrence of two identical sequences, one following the other, in a chromosome segment.

REVERSE TANDEM

is a non-tandem duplication that brings the new copy to a region that is transcribed in the opposite direction so that the copy actually produces the same amino acid as the original

DISPLACED HOMOBRACHIAL

The repeated segment doesn’t foolow the arc.

DISPLACED HETEROBRACHIAL

The repeated segent is found on the other side of the arc.

INVERSION

is a chromosome rearrangement in which a segment of a chromosome is reversed end to end.

2 KINDS OF INVERSION

1. Paracentric Inversion2. Pericentric Inversion

PARACENTRIC INVERSION

do not include the centromere and both breaks occur in one arm of the chromosome.

PERICENTRIC INVERSION

include the centromere and there is a break point in each arm.

TRANSLOCATION

is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes

2 KINDS OF TRANSLOCATION

1. Reciprocal2. Non reciprocal

RECIPROCAL

are usually an exchange of material between nonhomologous chromosomes.

NON RECIPROCAL

type of rearrangement involves two acrocentric chromosomes that fuse near the centromere region with loss of the short arms.

THE END