question_answer 17)

  Conditions of a karyotype 2n ± 1 and 2n ± 2 are called (a) aneuploidy                       (b) polyploidy                (c) allopolyploidy              (d) monosomy

Answer:

                  (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 chromosomes but not a complete set. Polyploidy is defined as the addition of entire set of chromosome. The polyploidy can be triploidy (3n), tetraploidy (4n), pentaploidy (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 diploid set of chromosome (2n-1).