Changes in chromosome structure Flashcards Preview

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Flashcards in Changes in chromosome structure Deck (15):
1

deletion

where chromosomes have missing parts due to chromosomal segrments which lack the centromere breaking off

2

deletion- where chromosomes have missing parts- detail

-a deletion is the loss of art of one chromosome arm -deletions can be small, only covering a part of one gene -deletion can be large, with chromosomes missing pieces large enough to be visualised on a karyotype

3

karyotype

a test to identify and evaluate the size, shape and number of chromosomes in a sample of a body cell

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deletions can be small

only covering a part of one gene

5

deletions can be large

with chromosomes missing pieces large enough to be visualised on a karyotype

6

when chromosomes have mixed up pieces

inversion and translocations

7

inversions

chromosomal segment is lost and rotated 180 degree and then reinserts in the same position

-all the same genes are the same but the order is inverted

-inversions are balanced rearrangements- no loss or gain of genetic material -meiosis

8

inversions can lead to

deletions or duplication

9

how are inversions created

to create an inversion, a segment of the chromosome is cut out, flipped and reinserted into he chromosome in the opposite orientation in the same place

10

translocation

a rearrangment involving a part of one chromosome that has broken off and reattached to a DIFFERENT part of the chromosome or to a non-homologous chromosome

11

reciprocal translocation

usually an exchange of material between nonhomologous chromosomes. -usually harmless and can be found in prenatal tests

12

robertsonian translocation

(ROB) is a rare form of chromosomal rearrangement that, in humans, generally occurs in the five acrocentric chromosome pairs, namely 13, 14, 15, 21 and 22. Other Robertsonian translocations can occur, but do not lead to a viable fetus

13

duplications

chromosomes can have extra fragments from homologous chromosomes 

-duplications of sequences of DNA already present

14

what do duplications play an important role in

duplications play an important role in the evolution own the genome

15

reciprocal translocation

2 fragments switch places on non homologous chromosomes