Both genes and chromosomes play equally pivotal roles in holding and transmitting genetic information. There are several significant differences between the two. 

Genes:

• Genes are located on the chromosome. A single gene has a fixed location or locus on a chromosome. 

• Genes are composed of either DNA or RNA and are not visible under the microscope.  

• Gene mutations are small, sometimes silent. They occur either in DNA replication or consequent DNA damage. Gene mutations include point mutations and frameshift mutations, insertions and deletions.

Chromosomes

• Chromosomes are condensed structures made up of nucleic acid and proteins. A single chromosome is made up of many genes.

• Chromosomes are composed of DNA, RNA and proteins and are visible under the microscope.

• Chromosomal mutations occur in homologous recombination and are relatively large. Chromosomal mutations result in chromosomal aberrations such as rearrangement, deletion, duplication, and inversion of genes.