Question

Smallest human gene is that of
A) Maleness
B) Blood group
C) Thymus activity
D) Shape of nose

Answer 1

Hint:A gene is defined as the unit of DNA responsible for the appearance of inheritance of characters. These genes are present on chromosomes that are the long DNA molecules. There are 23 pairs of chromosomes in humans.

Complete answer:
Genomics is the study of sequencing and analyzing genome, structure and functioning of genes.
A very ambitious project of sequencing the human genome was launched in the year 1990. It was started by Watson and later Franscis Collins and Venter Craing also coordinated the project.
It was a mega project started by the U.S. Department of Energy and National Institute of Health. The total estimated cost of the project was approximately 9 billion US dollars.

This project revealed some salient features of human genome like:
->Human genome has 3164.7 million nucleotide bases.
->3 billion base pairs of the human genome were identified, under this project.
->It was revealed that repeated sequences make up a large portion of the human genome
->The average gene consists of 3000 bases but size varies greatly with the TDF gene consisting of only 114 bases.
->The functions of over 50 percent of discovered genes are unknown and less than 2% of genome codes for proteins.
->Chromosome 1 has the largest number of genes and it was last to be sequenced in 2006 while Y has the fewest gene.
->So from all of this, it can be concluded that the smallest human gene is that of maleness.

Hence the correct answer is option ‘A’.

Note:Many non-human model organisms like bacteria, yeast, Caenorhabditis elegans, Drosophila, Arabidopsis and rice have also been sequenced. This project has also helped in the rapid development of a new area in biology called Bioinformatics.