What are tetrasomics?

Answer 1

Addition of a pair of chromosomes to a diploid set results in tetrasomic condition. Tetrasomics may be represented as 2N+2. Tetrasomics may arise when two abonormal gametes produced as a result of non-disjuction unite, with each gamete carrying an extra chromosome of the same pair as shown below. AABBCCDD a diploid cell----meiosis and non disjuction AABC Gamete carrying an extra chromosome--- BC Gamete short of one chromosome. Now if this Gamete (AABC) unites with another gamete of the same kind (AABC), we get tetrasomic AAAABBCC.