\name{seqSkew}
\alias{seqSkew}
\alias{GCcontent}

\title{compute the strand assymetries from one sequence fragment}
\description{
 compute the strand assymetries from one sequence fragment
}
\usage{
seqSkew(seqno = 0, from=1,to=0,strand=getStrand(),case = "all")
GCcontent(seqno = 0, from=1,to=0,case = "all",...)
}

\arguments{
  \item{seqno}{Input sequence number. (bufseq)}
  \item{from,to}{Begining and ending of sequence, can be
    vectors. 0 represent the last nucleotide and 1 the first one.}
  \item{case}{"all"}
  \item{strand}{strand}
  \item{...}{other parameters}
}

\value{
a data frame with 4 columns as follow
\item{TA skew or TA pourcent}{(T-A)/(T+A) or count(TA) / count(TAGCN)}
\item{GC skew or GC pourcent}{(G-C)/(G+C) or count(GC) / count(TAGCN)}
\item{total skew or C pourcent}{TA+GC skews or count(C) / count(TAGCN)}

}



\author{Yves d'Aubenton and Emna}

\seealso{\code{\link{densityProfile}},\code{\link{bankDensityProfile}},\code{\link{compoSeq}}}


\keyword{utilities}
\examples{
     s<-"CGTACGTAGTAGCTAGCTAGCTAGCTAGCTGATCGATGCTAGCTGATCGATGCT"
     placeString(s,seqno=0)
     x<-c(1,8,15,50)
     y<-c(5,12,19,54)
     seqSkew(seqno=0,from=x,to=y,strand=0)

     seqSkew(seqno=0,from=x,to=y,strand=1)

     GCcontent(seqno=0,from=x,to=y)



}