Q.2.  Conditions of a karyotype 2n±1 and 2n±2 are called

a.  aneuploidy

b.  polyploidy

c.  allopolyploidy

d.  monosomy

 

(a) Aneuploidy involves changes in chromosome number by additions or deletions of less than a whole set. In this case organism gains or loses one or more chromosome. The polyploidy can be triploidy (3n), tetraploidy (4n), p[entaploidy (5n), etc.

Allopolyploidy is the polyploidy in which chromosome sets are non-homologous. In other words, we can say that the allopolyploids are derived from a stock which is heterozygous. Monosomy is the process in which one chromosome is removed from a diploid set of chromosome (2n-1).