In a cross between white-flowered parents, $F_1$ progeny was uniformly purple-flowered. The $F_2$ progeny showed a phenotypic ratio $9 : 7$ between purple-flowered and white-flowered plants. The above result indicates that the flower colour is controlled by
Two alleles
One allele
Three alleles
Four alleles
Mirabilis jalapa is a good example of
Which of the following parental combination has produced mutant offspring?
Mendel's experimental material was
Both sickle cell anaemia and Huntington’s chorea are
The salivary gland chromosomes in the dipteran larvae are useful in gene mapping because