Aneuploidy

• Refers to one or few chromosomes extra or missing from 2n.
• It is of following types:

i) Nullisomic: One chromosome pair missing (2n+/-)

ii) Monosomic: One chromosome missing (2n-2)

iii) Double monosomic: One chromosome from each of two different pairs missing.(2n-1-1)

iv) Trisomic: One chromosome extra (2n+1)

v) Tetrasomic: One chromosome pair extra (2n+2)

Uses of Aneuploids

• Used to determine the phenotypic effects of loss or gain of different chromosome.
• Useful in production of substitution lines.
• Useful in identifying chromosomes involved in translocation.
• Locating a linkage group and a gene to a particular chromosome.
• Produce alien addition and alien substitution which are useful in gene transfer from one species to another.

Production of Aneuploids

• From autotriploid plants
• Progeny from a cross between tetrasomic (2n+2) and diasomic (2n) plants.
• A synaptic and desynaptic plants.
• From translocation heterozygoytes.