chromosomal aberrations

CHROMOSOMAL ABERRATIONS(identification using karyotyping)

Prepared by:Mr. Nikko Lorenz P. Lawsin

MASEd Biology

C H R O M O S O M E S

D I S J U N C T I O N

E X C E S S

L A C K I N G

T R A N S L O C A T I O N

D E L E T I O N

D U P L I C A T I O N

I N V E R S I O N

Causes:1. Non-disjunction in Meiosis

2. Inability of the Spindle fiber to attract the chromosomes.

Based on Chromosomal Number

(Euploidy or Aneuploidy)

Based on structure

CHROMOSOMAL ABERRATIONS

Euploidy – Sets of Chromosomes alterations. If 2n is normal,Therefore,3n is TRIPLOID4n is TETRAPLOID

Aneuploidy – single number alterationsExample, if 2n is normal,2n + 1 is Trisomy

Trisomy (2n + 1) In human, 46 Chromosomes (23

pairs) 2(23) + 1 = 47

Trisomy 21 – Down syndrome Trisomy 18 – Edward Syndrome Trisomy 13 – Patau Syndrome Trisomy 23 (XXY) – Klinefelter’s

syndrome

Monosomy (2n - 1) In human, 46 Chromosomes (23 pairs) 2(23) - 1 = 45

XO syndrome (Turner’s syndrome) – defiency of X or Y in sex chromosomes

Monosomy in autosomes is not viable

Double Trisomy (2n + 1) + 1

In human, 46 Chromosomes (23 pairs) [2(23) + 1 ] + 1= 48

Tetrasomy (2n + 2)

In human, 46 Chromosomes (23 pairs) 2(23) + 2 = 48

Nullisomy (2n - 2) In human, 46 Chromosomes (23

pairs) 2(23) - 2 = 44

Based on Structure

Deletion Inversion Translocation Duplication

Deletion

Deletion of DNA or Chromosomes’ part or segment

Deletions

A B C D E F G H I J K L

The TRAITS that are controlled by the genes of JKL, are missing which might result to some disorders.

A B C D E F G H I

NORMAL

DELETED

Duplication

Duplication of DNA or Chromosomes’ segment

DUPLICATION

A B C D E F G

The TRAIT(s) that is/are controlled by the genes of CDE is duplicated which may also produce aberration such as polymorphism

A B C D E C D E F G

NORMAL

DUPLICATED

Translocation

Transfer of Chromosome’s segment into non-homologous chromosomes

TRANSLOCATION

A B C D E F G H I

EFG gene which controls other trait(s) might not be functional since it displaced into another locus.

A B C D H I

NORMAL

TRANSLOCATED

V W X E F G Y Z

CHROMOSOME #4

CHROMOSOME #4

CHROMOSOME #8

Identify the ff. chromosomal aberrations

based on number &

structure using the ff. karyotype

Trisomy 23 (XXY) or Klinefelter Syndrome

Trisomy 21 (XXY) or Down Syndrome

Triploid

Trisomy 18 (XXY) or Edward Syndrome

Trisomy 21 (XXY) or Down Syndrome

Tetraploid

Monosomy (X0) or Turner Syndrome

Trisomy 23 (XXY) or Klinefelter Syndrome

Trisomy 13 (XXY) or Patau Syndrome

Trisomy 13 (XXY) or Patau Syndrome

Tetrasomy

Double Trisomy

A B C D E F G H I J K L

The TRAITS that are controlled by the genes of JKL, are missing which might result to some disorders.

A B C D E F G H I

NORMAL

????

A B C D E F GA B C D E C D E F G

NORMAL

????

A B C D E F G H I

EFG gene which controls other trait(s) might not be functional since it displaced into another locus.

A B C D H I

NORMAL

????

V W X E F G Y Z

CHROMOSOME #4

CHROMOSOME #4

CHROMOSOME #8

POST-ACTIVITY: CREATE YOUR OWN KARYOTYPE

QUIZ TIME

QUIZ TIME: Solve this problem with complete solution

There are 52 chromosomes in a normal cell of unknown organisma. Identify the number of chromosomes of a haploid cell (n). (2pts)b. Identify the aberrations of the following chromosomes

considering the given above. Show your solution. b.1 104 chromosomes (2pts) b.2 53 chromosomes (2pts) b.3 50 chromosomes (2pts) b.4 78 chromosomes (2pts)