The question is, is this meaningful or classifiable. Many other animal species have been around much longer or they have shorter life spans, so they've had many more opportunities to accumulate genetic variants. Penguins, for example, have twice as much genetic diversity as humans. Fruit flies have 10 times as much.
Who wore number 20 for Boston bruins? According to azhockey.com, the number 20 has been worn by 23 different Bruins players. In this decade, Darren Van Impe, Eric Manlow, Martin Lapointe, and Wayne Primeau have all worn 20. Players to wear the jersey in the 1980s-90s were Al Secord, Mike O'Connell, Dwight Foster, Tommy Lehmann, Bob...
You recently may have noticed Ivan Pudge Rodriguez' jersey number looking different. Seven was his number for much of his career, except for when he went to the New York Yankees (who've retired No. 7 in honor of Mickey Mantle) and with the Astros (where No. 7 is retired in honor of Mr. Craig Biggio). So, to compensate, he wore No. 12. And now, Rodriguez is wearing No. 77.