A new synthetic yeast chromosome has been created, which could lead to dramatic new advances in molecular biology. Researchers believe this new development could lead to bio-factories capable of quickly manufacturing chemicals, including medicines and fuels. 

Jef Boeke, from New York University led the research, attempting to create the first genetic code, written piece-by-piece. For the first time ever, biologists were able to create a working yeast chromosome, Syn 3, from scratch. 

In 2010, researchers created the world's first synthetic bacteria, and this new advance may help pioneer future development of man-made genetic codes. 

"The complete design and synthesis of [this gene]... establishes [brewer's yeast] as the basis for designer eukaryotic genome biology," researchers wrote in the accompanying article. 

Brewers yeast, also known as Saccharomyces cerevisiae, is also being explored as the basis of new biofuels. 

The common food ingredient could also be used to develop a new drug designed to help combat malaria. By incorporating human DNA into the S. cerevisiae, it may be able to develop screening tests for a number of diseases and disorders. 

"Biology is now undergoing a similar transition from the age of deciphering DNA sequence information of the genomes of biological species to a synthetic genome age," researchers wrote on the project website.

The project began with a program called Build-a-Genome, launched seven years ago. Over 100 students each assembled tiny pieces of genetic code, and sent their creations to Boeke. Researchers removed "junk DNA" which do not code for proteins. They then inserted markers at certain points in the code, allowing the team to easily move sections of the genetic material. 

Researchers made over 500 changes to the code, and were surprised how even small changes could have dramatic and unexpected results. 
"We didn't know ahead of time whether it was going to work out or not. We know of many instances where we make one single base change and it will kill the yeast dead," Boeke told the press. 

Unlike humans, who possess 23 pairs of chromosomes in our DNA, yeast use just 16 pairs. The synthetic genetic code developed by Boeke and his team mimicked the 3rd of those chromosomes, which controls mating, as well as some other functions. 

To test their research, the team substituted sections of their custom-made code into the natural genetic codes of yeast. They found the codes worked fine, even after removing nearly 43,750 base pairs from the 316,617 present in natural yeast. 

Once the code was shuffled, the new code became able to mate. 

Production of the synthetic yeast chromosome was profiled in the journal Science.