Question

Which human chromosome has the fewest genes?

Answer 1

Insights into the sequencing of the human genome has shown that the smallest chromosome in humans has the least number of genes.

Complete answer: Humans have 23 pairs of autosomes and one pair of sex chromosomes.
1. The y chromosome is a male determining gene because male lineage is usually traced using the Y chromosome.
2. Different approaches were used in identifying the number of genes in a chromosome.
3. Genes on sex chromosome help in sex determination and also provides instructions for protein synthesis.
4. The Y chromosome is one of the smallest chromosomes in humans.
5. It has the least number of genes that are approximately 55 genes and the X chromosome has about 900 genes.
6. The Y chromosome typically represents about 2-3 percent of the total DNA in the cells.

Additional information: The Y chromosome consists of a "male-determining gene," the SRY gene, that causes testes to form in the embryo and forms the development of external and internal male genitalia.
If there is a mutation in the SRY gene, the embryo will develop female genitalia despite containing XY chromosomes.

Note: The Y-chromosome has a limited number of genes because the chromosomal genes have degenerated during evolution.
The Y chromosome is also known as the gene-poor chromosome.
Much of the Y chromosome is composed of repeating DNA sequences.