Explanation

Gn.Ex : gene number, exon number (for reference)
Type  : Init = Initial exon
        Intr = Internal exon
        Term = Terminal exon
        Sngl = Single-exon gene
        Prom = Promoter
        PlyA = poly-A signal
S     : DNA strand (+ = input strand; - = opposite strand)
Begin : beginning of exon or signal (numbered on input strand)
End   : end point of exon or signal (numbered on input strand)
Len   : length of exon or signal (bp)
Fr    : reading frame (a codon ending at x is in frame f = x mod 3)
Ph    : net phase of exon (length mod 3)
I/Ac  : initiation signal or acceptor splice site score (x 10)
Do/T  : donor splice site or termination signal score (x 10)
CodRg : coding region score (x 10)
P     : probability of exon (sum over all parses containing exon)
Tscr  : exon score (depends on length, I/Ac, Do/T and CodRg scores)

Comments

The SCORE of a predicted feature (e.g., exon or splice site) is a log-odds measure of the quality of the feature based on local sequence properties. Thus, for example, a predicted donor splice site with score > 100 is excellent; 50-100 is acceptable; 0-50 is weak; and below 0 is poor (probably not a real donor site).

The PROBABILITY of a predicted exon is the estimated probability under GENSCAN's model of genomic sequence structure that the exon is correct. This probability depends in general on global as well as local sequence properties. This information can be used to assess the reliability of the predicted exon, e.g., it would be better to design PCR primers based on a predicted exon with probability > 0.95 than one with lower probability.