Out with the old, in with the new. That's pretty much been the mantra at Illumina (Nasdaq: ILMN) for the last year, as the company's DNA-sequencing business took off and its microarray business lagged.

But the new mantra seems to be, "Stick with the old, in with the new." Illumina's sequencing sales continue to grow, and it looks like its microarray business has stabilized. Investors like the new system better; shares of the Stock Advisor pick are up 13% today.

Compare that to competitor Affymetrix (Nasdaq: AFFX), which only sells microarrays. Its shares fell more than 13% last Thursday after the company reported a miserable first quarter.

Sequencing gives very specific information about the genome, while microarrays provide more general information about the genome or expression of genes. Microarrays were traditionally used because they could provide a lot of information cheaply. As the price of sequencing has declined, its popularity among researchers has increased.

Illumina doesn't break down the exact ratio of sequencing to microarray products, but microarray consumables still make up more than half of the consumables sold, even though they declined year over year. Combined consumables rose 11% year over year.

The cheaper price of sequencing looks like it's reinvigorating the microarray business. A large consortium is working on sequencing a thousand genomes, which will give researchers plenty to look for in their samples. Illumina is making arrays containing those sequences available as the consortium releases each one. Sales of both microarrays and the machines that read them were up compared to last quarter.

I continue to think that drug companies Pfizer (NYSE: PFE), Bristol-Myers Squibb (NYSE: BMY), and Merck (NYSE: MRK) will be the true long-term beneficiary of the increasing use of sequencing. But in the short term, Illumina and its shareholders are certainly benefiting from the popularity.

What will be the next megatrend? Austin Edwards thinks he knows.

Find out why David Gardner picked Illumina for the Stock Advisor newsletter. Click here to get access to all the current Garner brothers' recommendations with a 30-day risk-free trial.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Pfizer is a recommendation of the Inside Value newsletter. The Fool has a disclosure policy.