Starting Jan 9th,you can transfer`Virgin Atlantic miles to Alaska Airline miles at 1 to 1.3

What does this mean?

This means, for eg.40k Amex MR points,you can transfer to Alaska Airlines(via SPG and Virgin) at 1MR to 0.8125 Alaska Air

40k Amex to 20k SPG
20k Spg to 25k Virgin
25k Virgin to 32.5k Alaska

40k Amex MR for 32.5k Alaska Airlines points