Question

Mutagenic effect of X-rays was discovered by

• A. Muller
• B. Luria
• C. Morgan
• D. Hugo de Vries

Answer 1

Answer: (A)

Muller

Muller used radioactivity to produce point mutations in the fruit fly Drosophila. Male fruit flies were exposed to relatively high doses of radiation and were then mated to virgin female fruit flies thereby, induced more than 100 mutations. It was concluded that radioactive particles traverse through the chromosomes and randomly affect the molecular structure of individual genes, making them either non-functional or with altered function. Salvador Luria and Max Delbrück demonstrated that favourable mutations, for example, antibiotic resistance in bacteria, are produced randomly on which natural selection acts. Hugo de Vries studied the inheritance of flower colour in evening primrose and called the sudden and random appearance of new characters as mutation but the observed mutations were actually chromosomal aberrations; he believed that single mutation created new species. Morgan worked on eye colour inheritance in Drosophila and induced mutation by radiations that produced white eyes fly in otherwise red-eyed generation. Thus, the correct answer is option A.