How and why Darwin’s Ark studies pet DNA differently

That means asking questions that do not yet have clear answers. Why do some cats develop certain diseases, like diabetes, while others do not? How does genetics shape behavior? What genetic variants increase disease risk? Answering those questions requires looking for relationships across the entire genome and studying many animals together, without knowing in advance what answers they will reveal.

As Darwin’s Ark Chief Scientist Elinor Karlsson explains, “Whole genome sequencing is really good for exploratory science where we don’t know what we’re going to find.”

The exploratory mindset is core to Darwin’s Ark’s mission and approach. “The goal is not just to provide you with answers about your pet,” Karlsson says. “It is to partner with you and your pet to make new scientific discoveries possible.”

“To tackle the hardest questions, you need large datasets,” - Kasia Bryc, PhD, Director of Research and Scientific Engagement.

How Darwin’s Ark makes discovery possible

So, if whole genome sequencing is the best way for researchers to look everywhere for answers to known and unknown questions, how does Darwin’s Ark actually make that work in practice?

The answer comes down to finding a method that balances genetic detail and dataset scale. Darwin’s Ark’s approach combines whole genome sequencing, low-pass sequencing, imputation, and large numbers of participants to make that possible.

If time and funds were unlimited, scientists would read every part of every animal’s genome many times over to build a very detailed picture. This is called high-coverage sequencing.

But that approach is expensive, and higher costs mean looking at the genomes of fewer animals.

For a project like Darwin’s Ark, that tradeoff matters.

“To tackle the hardest questions, you need large datasets,” says Kasia Bryc, PhD, Director of Research and Scientific Engagement. “Getting more participants is what allows us to make discoveries.”

The more animals researchers can compare, the easier it becomes to identify meaningful patterns in the similarities and differences across genomes.

High-coverage sequencing is just not financially feasible for research projects that operate at the scale of thousands of animals rather than a few hundred. That’s why Darwin’s Ark uses low-pass whole genome sequencing.

Low-pass sequencing still looks across the entire genome, but instead of reading each position many times, it aims to read each position only once or a few times on average. That produces a broad but less detailed picture of each animal’s DNA.

Because low-pass sequencing reads each position fewer times, the data at any given spot may be less certain. A detected difference could represent a genuine genetic variant or merely a sequencing error. To mitigate this uncertainty, the data is compared with a reference set built from more than 1,000 cat genomes that were sequenced in much greater detail. By analyzing shared patterns across many animals, researchers can fill in gaps and improve accuracy.

This process, known as imputation, helps turn that initial data into a much more complete and reliable genetic picture. As Bryc explains, combining low-pass sequencing with imputation “gives us really high-quality genetic information that works very well for discovery.”

Why scale matters

In genetics, having more data is not just helpful—it is essential.

To understand how a trait or disease is connected to DNA, researchers need to compare many animals. That includes pets with a specific condition, as well as those without it. Only by looking across large groups can researchers start to identify meaningful connections. A single genome offers only limited insight on its own. But when thousands of genomes are studied alongside health and behavior data, much clearer signals appear.

“If you want to tackle the hard questions, you have to go big,” Bryc says.

This is especially true for complex traits, like behavior or common diseases, where many different genetic factors may be involved or where the drivers are a complicated combination of genetics and environment. Small studies can offer clues, but they often capture only part of the picture.

By combining whole genome sequencing with a large and growing number of participants, Darwin’s Ark can begin to identify patterns that would otherwise be impossible to detect. That includes rare genetic variants, as well as broader trends across different populations of cats and dogs.

Researchers need genetic and health information from many different animals, including both pets with specific conditions and those without them, to look for patterns that may help explain how genetics influences health and behavior.

Every genome adds context. Every data point helps sharpen the picture.

Your pet is part of something big

For Darwin’s Ark community scientists, that means your pet is part of something much bigger— DNA sequencing. You are part of building a deeper understanding of how genetics shapes the lives of the pets we love.

That kind of discovery takes time. It requires large datasets, careful analysis, and a willingness to explore questions that do not yet have clear answers.

But it also starts with something simple—community scientists joining the effort. Together, those small contributions create something powerful.

At Darwin’s Ark, each contribution may seem like a small step on its own, but powerful when combined with thousands of others contributing to scientific discovery.

Each community scientist sharing insights is invaluable in helping build a dataset that can lead to unexpected insights and more ambitious questions to explore. Whether you answer a survey question about your pet’s behavior, health, and environment or donate a DNA sample, you are adding valuable insights that enhance the understanding of genetic patterns and their significance.

A survey.
A DNA sample.
A pet parent willing to be part of the process.

And with every new participant, the picture becomes a little clearer, one pet at a time.