Question

Which of the following pairs is wrongly matched?
(a) XO type sex determination: Grasshopper
(b) Starch synthesis in pea: Multiple alleles
(c) T.H. Morgan: Linkage
(d) ABO blood grouping: Codominance

Answer 1

Hint: Characteristics that are expressed in organisms are controlled by genes. In most of the conditions, if it's a basic property shown by the organism, it will be controlled by a single gene and not multiple ones.

Complete step by step answer:
'Starch synthesis in pea: Multiple alleles' is the wrongly matched pair among the given pairs.
In pea plants, the synthesis of starch is controlled by a single gene with 2 alleles which are B and b. Considering the size of the grain it will be an example of incomplete dominance.
So the correct answer is ‘Starch synthesis in pea: Multiple alleles’.

Additional information: XO type of sex determination which is seen in grasshopper is also visible in other various insects. In this method of sex determination, A female will have two X chromosomes depicted as XX and the male will have only one X chromosome known as the XO, in this sex determination method.
- A phenomenon of genetic inheritance where the chromosome with a particular gene shows a tendency to be passed on together is known as linkage, which was found in Drosophila melanogaster by T.H. Morgan.
- If both alleles of a pair morphologically show themselves completely in the F1 hybrid, this phenomenon is called Codominance, which can be explained using the example of the human ABO blood group where the major four blood groups A, B, AB, and O are the responsibility of three alleles.

Note:
- Cows with Spots on them and flowers with two different colored petals are common examples of codominance.
- Sex determination in certain fishes and amphibians are controlled by environmental factors such as temperature.
- T.H Morgan was a legendary American biologist and geneticist who won the Nobel Prize in 1933.