Definition: �Joined� and �split� genes
JG > 1, tendency to join multiple actual genes into one prediction
SG > 1, tendency to split actual genes into separate gene predictions
Inspired by Hayes and Guig� (1999), unpublished.
SG = -------------------------------------------
# Predicted genes that overlap actual genes
# Actual genes that overlap one or more predicted genes
JG = -------------------------------------------
# Actual genes that overlap predicted genes
# Predicted genes that overlap one or more actual genes