Question

In Melandrium plants, the presence of 2 pairs of autosomes and an allosomes composition of XXY would make them
A. Males
B. Females
C. Sterile
D. Intersexes

Answer 1

Hint: Melandrium album is a dioecious species of angiosperm containing a set of 2n = 24 chromosomes. They have the heteromorphic sex chromosomes, namely, XY (males) and XX (females). Universally, the presence of an X chromosome determines the female offspring and the presence of Y chromosome determines the male offspring.

Complete step by step answer: Melandrium album is a dioecious plant that has two heteromorphic sex-determining chromosomes, X and Y for males and the XX for female sex determination respectively. Melandrium possesses a novel system of sex determination. In this system, the Y chromosome produces a strong and dominant male offspring. In these plants, two pairs of autosomes are present and the allosomal composition XXY results in male offsprings. Many polyploid and aneuploid Melandriumdioecious plants are obtained and studied for the role of X and Y chromosome, along with the autosomes in sex determination. The plant shows many variations in chromosomal inheritance including 2A XX, 2A XXY, 4A XXX, 4A XXXY, 4A XXXX, 4A XXXXY, and 4A XX, 4A XXY, 4A XXYY. In each of these variations, the number of Y chromosomes is responsible for the male offspring.
So, the correct answer is option A.

Additional information: The X-chromosomes were first discovered in 1905 by Wilson and Stevens. The XY system takes place in a large variety of animals which includes Drosophila and almost all the mammals, along with a few plants, for example, Lychnis.

Note: The X and Y chromosomes are known as sex chromosomes. The remaining chromosomes are known as somatic chromosomes which are similar in all sexes are also known as autosomes. The sex determination which includes X and Y chromosomes is known as the XX-XY system.