Relationships are already a challenge for some, and now it seems that your DNA plays a huge role in determining if you'll have a happy relationship or marriage.

Researchers from the University of California, Berkeley, found a gene involved in the regulation of serotonin can predict how much our emotions affect our relationships. According to Daily News:

The team found a link between relationship fulfillment and a gene variant, or allele, known as 5-HTTLPR. All humans inherit a copy of this gene variant from each parent, they said.

Study participants with two short 5-HTTLPR alleles were found to be most unhappy in their marriages when there was a lot of negative emotion, such as anger and contempt, and most happy when there was positive emotion, such as humor and affection. By contrast, those with one or two long alleles were far less bothered by the emotional tenor of their marriages. The study involved 100 married subjects, with researchers studying their genotytpes and observing the subjects with their partners over a period of 13 years.

"We are always trying to understand the recipe for a good relationship, and emotion keeps coming up as an important ingredient," said Levenson.

However, researchers note that it doesn't mean that couples with different variations of 5-HTTLPR are incompatible - it's just that those with two short alleles are more likely to thrive in a good relationship and suffer in a bad one.

"Individuals with two short alleles of the gene variant may be like hothouse flowers, blossoming in a marriage when the emotional climate is good and withering when it is bad," said researcher Claudia M. Haase. "Conversely, people with one or two long alleles are less sensitive to the emotional climate."