Mars sample-return program axed in new US spending bill; MSRB3-linked ear-length gene found in dogs | Nature Briefing

In this Nature Briefing episode, the Mars sample-return mission faces cancellation due to a new US spending bill, though some NASA future missions funding remains. Separately, dog genetics researchers link ear length variation to DNA variants near the MSRB3 gene, offering a genetic explanation for why some breeds have long floppy ears while others are short or upright. The show reflects on the implications for planetary science and canine biology, highlighting how samples from Mars and canine ears can illuminate life detection strategies and evolutionary processes. Links to full stories and sign-up for Nature Briefing are provided in the show notes.

Mars sample-return funding and policy update

The episode opens with a discussion about the Mars sample-return mission, focusing on a recent spending bill that effectively cancels the government-backed return plan. While the proposal to bring Perseverance rock samples back to Earth is paused, the bill preserves funding for many NASA missions and sets aside funds for continued technology development under the NASA Future Missions programme, potentially enabling a future path for sample return if priorities shift. The conversation also touches on the scientific questions at stake, including whether Martian samples can answer questions about life, habitability, and planetary history, and highlights the role of ongoing tech development in making future returns more affordable or feasible.

"the can has struck the end of the road" - Nick Petridge Howe

Canine ear length and the MSRB3 genetic link

The second story shifts to dog genetics. Researchers analyzed DNA from thousands of canines, including wolves and coyotes, to identify genetic associations with ear length. They point to variants near the MSRB3 gene, not the gene itself, as being linked to ear carriage, including whether ears are long and floppy or more upright. MSRB3 encodes an antioxidant protein and has prior associations with hearing in humans and ear morphology in other livestock species. The study discusses how selective breeding and climate adaptation have shaped canid ear morphology and suggests further work within single breeds, such as golden retrievers, to refine the genetic basis of ear length.

"MSRB3 near-DNA variants linked to ear length" - Benjamin Thompson

Implications and future directions

The show closes by reflecting on how these two stories—Mars science and canine genetics—illustrate broader themes in science policy and genetic research. They emphasize the need to track funding decisions that influence ambitious planetary science while also pursuing precise genetic mapping to understand complex traits shaped by breeding and environment. Readers are invited to read the full Nature briefing stories and sign up for future updates to stay informed about Mars sample-return planning and canine genetics advances.

"science at its core" - Nick Petridge Howe