, ▁and ▁what ▁is ▁being ▁compared . ▁These ▁programs ▁and ▁their ▁details ▁are ▁listed ▁below : ▁ ▁B LA ST ▁is ▁actually ▁a ▁family ▁of ▁programs ▁( all ▁included ▁in ▁the ▁bl ast all ▁executable ). ▁These ▁include : ▁N uc le ot ide - n uc le ot ide ▁B LA ST ▁( blast n ) ▁This ▁program , ▁given ▁a ▁DNA ▁query , ▁returns ▁the ▁most ▁similar ▁DNA ▁sequences ▁from ▁the ▁DNA ▁database ▁that ▁the ▁user ▁spec ifies . ▁Prote in - prote in ▁B LA ST ▁( blast p ) ▁This ▁program , ▁given ▁a ▁protein ▁query , ▁returns ▁the ▁most ▁similar ▁protein ▁sequences ▁from ▁the ▁protein ▁database ▁that ▁the ▁user ▁spec ifies . ▁Position - Spec ific ▁Iter ative ▁B LA ST ▁( P SI - B LA ST ) ▁( blast pg p ) ▁This ▁program ▁is ▁used ▁to ▁find ▁distant ▁relatives ▁of ▁a ▁protein . ▁First , ▁a ▁list ▁of ▁all ▁closely ▁related ▁prote ins ▁is ▁created . ▁These ▁prote ins ▁are ▁combined ▁into ▁a ▁general ▁" profile " ▁sequence , ▁which ▁summar ises ▁significant ▁features ▁present ▁in ▁these ▁sequences . ▁A ▁query ▁against ▁the ▁protein ▁database ▁is ▁then ▁run ▁using ▁this ▁profile , ▁and ▁a ▁larger ▁group ▁of ▁prote ins ▁is ▁found . ▁This ▁larger ▁group ▁is ▁used ▁to ▁construct ▁another ▁profile , ▁and ▁the ▁process ▁is ▁repeated . ▁By ▁including ▁related ▁prote ins ▁in ▁the ▁search , ▁P SI - B LA ST ▁is ▁much ▁more ▁sensitive ▁in ▁pick ing ▁up ▁distant ▁evolution ary ▁relationships