Pioneering forensic and crime procedural shows such as CSI (2000 to 2015) and Law & Order (1990 to 2010) stuck resolutely to a formula: They focused on the nitty-gritty of solving each case-of-the-week featured, not so much on the people solving them.

Debuting in 2005, Bones broke the mould by delving into the lives of its team of investigators, led by brilliant forensic anthropologist Temperance "Bones" Brennan, who also brought a quirky sense of humour to this morbid milieu.

As the comedy-drama heads towards the end of its 12th and final season on Fox HD (Wednesdays at 9pm, Singtel TV Channel 330 and StarHub TV Channel 505), stars Emily Deschanel and David Boreanaz tell The Straits Times that they had to fight to keep the show character-driven rather than just a dry procedural.

Deschanel plays Bones and Boreanaz is her partner Seeley Booth, the Federal Bureau of Investigation agent who brings her unsolved cases relating to human remains.

The two characters fall in love over the course of the series and are now married with two children.

Boreanaz, 47, says: "When it started, it was very ground-breaking in the fact that we really went away from the procedural aspect of it and dove into the character relationships."

Deschanel, 40, adds that the humorous banter between the characters was also something of a first for forensic procedurals back then.

"We allowed humour to play a part in a show about death, which I think hadn't happened as much before," says the actress, for whom this was a career-defining series, far eclipsing her previous supporting roles in films such as Cold Mountain (2003).

"It was about the give-and-take between the characters", says Boreanaz, who played a vampire on the cult series Buffy The Vampire Slayer (1997 to 2003) and its spin-off Angel (1999 to 2004).

He and his co-star "were always against" making Bones purely a procedural, he reveals.

"And we fought for that, and we fought, fought, fought. And it finally became about the relationships," says the actor, who has a son, 14, and a daughter, seven, with his wife, model Jaimie Bergman, 41.

Over the last 12 years, he and Deschanel have become more involved in steering the series behind the camera as well.

The pair co-produce the show with Kathy Reichs, the forensic anthropologist on whose life it is loosely based.

In addition, Boreanaz has directed almost a dozen episodes, including the series finale that will air at the end of this month, while Deschanel made her directorial debut with the season premiere episode last month.

Boreanaz notes that the character-driven sensibilities of the series have since percolated through to other crime procedurals.

"A lot of those shows that were around us are now more geared towards relationship first and procedural later," he says.

Yet the cast and crew still "pride ourselves on being completely different" from CSI, Law & Order and other hugely popular series that have come to define the genre.

Deschanel says: "They are all great shows, but they're different. We're all dealing with similar things - forensic science, solving crimes - but that's almost a side-note (for us)."

On Bones, "it's really about the characters and what's going on, and you also know about the characters and their personal lives more than you ever knew about the main characters on CSI", she observes.

"I loved watching those shows, but I would always think those actors that got to do the guest spots always got to do the more interesting stuff. Because the people who were series regulars were just solving the crime usually and it was very rare that you got to see a glimpse of their personal life.

"So it was such a treat to be able to do a show where you really got to do emotional stuff, character stuff and relationship stuff as a series regular," says the star, who is married to actor David Hornsby, 41, and has two sons aged five and one.

Her sister is Zooey Deschanel, the 37-year-old singer and star of sitcom New Girl (2011 to the present).

Emily Deschanel also points out that Bones, which co-stars Michaela Conlin as a forensic facial-reconstruction expert and Tamara Taylor as a pathologist, is one of the rare TV series to feature "so many female characters in science".

"You know, the lab was really run by women - the women all had larger offices than the men in the show," she says, grinning.

"I hope that that influences girls in real life to go into science if they're interested and hopefully (leads to) more shows showing women in power and women in science."

•Bones Season 12 airs on Fox HD (Singtel TV Channel 330, StarHub TV Channel 505) on Wednesdays at 9pm.