Question

Trisomics were first reported by _____ *

Answer 1

Answer:

A.F. Blakeslee

Explanation:

Trisomics are those organisms, which have an extra chromosome (2n + 1). Since the extra chromosome may belong to any one of the different chromosomes of a haploid complement, the number of possible trisomics in an organism will be equal to its haploid chromosome number. For instance, we know that haploid chromosome number in barley is n = 7, consequently, seven trisomics are possible. Trisomics, where extra chromosome is identical to twohomologues, are called primary trisomics. Besides these, there are secondary and tertiary trisomics. While a secondary trisomic means that extra chromosome should be an isochromosome (both arms genetically similar), a tertiary trisomic would mean that extra chromosome should be the product of a translocation (Fig. 20.2). Trisomics were obtained for the first time in Datura stramonium (jimson weed) by A.F. Blakeslee and his co-workers.