A Northern California family received an improbable surprise when genetic testing showed the senior dog they adopted from a San Francisco rescue organisation is the biological father of their pet that died earlier this year. Jillian and Matthew Reiff adopted the rat terrier–chihuahua mix, named Ziggy, from Muttville Senior Dog Rescue in July, four days after the death of their longtime companion Rufus, also a rat terrier mix adopted in 2016 from the city’s SPCA. Ziggy’s close resemblance and behaviour prompted the family to submit a saliva sample to Embark Veterinary, a consumer pet-DNA testing company. Embark’s report found an identical DNA match, confirming that Ziggy, estimated to be about 12 years old, sired Rufus. “It’s the craziest story in all of the rescues we’ve ever done,” Muttville founder Sherri Franklin said, noting the shelter has placed more than 13,000 senior dogs since its founding in 2007. The discovery highlights both the growing use of genetic testing in pet care and the benefits of adopting older animals, which shelters say helps ease crowding and lowers euthanasia rates.