I'm curious about the phrase "open lines", used in a quote from the Bloodhorse.com article about Americain standing at Swettenham in Australia -
"Americain is out of the Arazi mare America and has duplicated open lines to Plucky Liege, Blossom Time, and Sierra in a similar but slightly stronger genetic pattern to the recent English Derby (Eng-I) winner New Approach, who is one of the world's hottest young stallions," Kevin Bamford said.
I understand the "duplicated" part, but what exactly does the "open lines" part mean?
Here's a link to the full article, if you want to read more -
http://www.bloodhorse.com/horse-racing/articles/75471/americain-to-stand-at-swettenham-stud-in-2013