Two human relaxin genes are on chromosome 9

Area of Science:

• Genetics
• Molecular Biology
• Evolutionary Biology

Background:

• Two distinct human relaxin gene sequences, H1 and H2, were cloned.
• Structural similarities suggest relaxin and insulin evolved from a common ancestral gene via duplication.

Purpose of the Study:

• To determine if the two cloned human relaxin gene sequences are alleles or distinct genes.
• To investigate the evolutionary relationship between human relaxin and insulin genes by determining their chromosomal locations.

Main Methods:

• Genomic DNA was analyzed using Southern gel electrophoresis.
• Chromosomal localization was determined using mouse/human cell hybrids.

Main Results:

• Southern gel analysis confirmed the presence of both relaxin genes in all individuals, making them unlikely to be alleles.
• Both human relaxin genes were mapped to the short arm of chromosome 9.
• The human insulin gene was found to be located on a different chromosome.

Conclusions:

• The human genome contains two distinct relaxin genes, H1 and H2.
• The human relaxin genes and insulin gene are located on separate chromosomes, supporting their divergence from a common ancestor.
• Both human relaxin genes reside on chromosome 9, specifically its short arm.