\name{alpha}
\alias{alpha}
\docType{data}
\title{ Genetic Components of Alcoholism }
\description{
  Levels of expressed alpha synuclein mRNA in three groups of allele lengths
  of NACP-REP1.
}
\usage{data("alpha")}
\format{
  A data frame with 97 observations on the following 2 variables.
  \describe{
    \item{\code{alength}}{allele length, a factor with levels \code{short},
                         \code{intermediate} and \code{long}.}
    \item{\code{elevel}}{expression levels of alpha synuclein mRNA.}
  }
}
\details{

  Various studies have linked alcohol dependence phenotypes to chromosome 4.
  One candidate gene is NACP (non-amyloid component of plaques),
  coding for alpha synuclein. B\"onsch et al. (2005) found longer alleles of
  NACP-REP1 in alcohol-dependent patients compared with healthy
  controls and report that the allele lengths show some
  association with levels of expressed alpha synuclein mRNA.

}
\source{

  D. B\"onsch, T. Lederer, U. Reulbach,  T. Hothorn, J. Kornhuber and S. Bleich
  (2005), Joint Analysis of the NACP-REP1 Marker Within the Alpha
  Synuclein Gene Concludes Association with Alcohol Dependence.
  \emph{Human Molecular Genetics}, \bold{14}, 7, 967--971.

}
\examples{

  data("alpha", package = "coin")
  boxplot(elevel ~ alength, data = alpha)
  kruskal_test(elevel ~ alength, data = alpha)

}
\keyword{datasets}