i) -Change in nature, structure or number of chromosomes
a) Duplication
-A section of a chromosome is repeated/replicates
therefore genes are repeated.
b) Inversion
-Occurs when chromatids break at 2 places and when rejoining the middle piece rotates and joins in an inverted position.
c) Deletion
-Portion of a chromosome is left out after it breaks off and alters number and sequence of genes.
d) Translocation
-Occurs when a section of a chromatid breaks off and becomes attached to another chromatid of another chromosome.
e) Non-disjuntion
-Failure of homologous chromosomes/sister chromatids to separate/segregate during meiosis.
f) Polyploidy
-where the number of chromosomes double or triples.
-Beneficial in plants due to the following
•Increased yields/hybrid vigour//heterosis
•resistance to pests
•early maturity
•resistance to drought
•resistance to diseases
Anganifelix answered the question on April 17, 2018 at 12:22
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