CYTOLOGY

DUPLICATION

A portion of the chromosomes is replicated, resulting in extra genetic material.

A segment is repeated, can lead to extra gene copies

TANDEM DUPLICATION

This is the most straightforward type. The duplication segment is placed immediately next to the original segment in the same sequence.

REVERSE DUPLICATION

In this case, the duplicated segment is also placed next to the original, bit it is flipped or inverted.

DISPLACED DUPLICATION

The duplicated segment is not adjacent to the original. It "jumps" to a different location on the same chromosomes

homobrancial

the extra piece stay on the same arm of displaced duplication

heterobrancial

the extra piece moves to the opposite arm the centromere of displaced duplication

transposed duplication

This is a more 'extreme" version where the duplicated segment is attached to a completely different chromosomes (a non-homologous one)

deletion

occurs when a part of a DNA molecule is left during DNA replications. This results in a loss of genetic material. Because genes carry the instructions for making proteins, losing those genes means the body might miss out on vital "building instructions.

terminal delition

a break occurs at the end of the chromosomes, and the tip is lost.

intercalary deletion

Two breaks occur within the body of the chromosomes, the middle segment falls out, and the remaining ends stick back

inversion

occur when chromosomes breaks in two places, and the resulting segment rofates 180 degree before rejoining

paracentric inversion

the breaks occurs in only one arm of the chromosomes. The centromere is not included in the flipped segment

pericentric inversion

The breaks occur on opposite sides of the centromere. The centromere isincluded in the flipped segment

translocation

occurs when a segment of one chromosomes breaks off and attaches to a nonhomologous chromosomes (A chromosomes that isn't its natural pair)

reciprocal translocation

Two different chromosomes break and exchange segments. No genetic material is lost or gained-it just swapped houses.

robersonian translocation

This is a special type involving acrocentric chromosomes (chromosomes with very short upper arms, like 13, 14, 15, 21, and 22). The long arms of two chromosomes fuse together at the centromere, and the tiny short arms are lost.

EIOPLOIDY

where complete haploid sets of chromosomes are present.

POLYPLOIDY

if more than two sets are present.

ANEUPLOIDY

• Gain or loss of individual chromosomes (not whole sets)

• So the number is not a multiple of the normal set

Changes in the number of chromosomes • This is when an individual is missing a chromosomes from a pair or has more than two chromosomes of a pair.