"LIFE ON MARS" & "QUEER AS FOLK"
As it turns out, DCI Gene Hunt isn't the only character from 'Life On Mars' for whom we could posit a theory of relateeveety.
Since the show takes place in Manchester, England, there's a good chance that the main character, Sam Tyler, could be related to Vince Tyler of 'Queer As Folk', which also takes place in Manchester. As for Hazel Tyler, Vince's mum, she could either be related by marriage, or - if she had been an unwed mother - by blood.
Since "Tyler" is something of a common name, it probably would be stretching things a bit to claim that any one of them could also be related to Rose Tyler and her family of the Powell Estates in London ('Doctor Who').
But as they are now all listed as officially dead, it's a moot point....