The human anatomy dataset made available
in this resource consists of individual tissues for which the average
expression vector was created from at least 34 samples. The tissue
types were chosen such as to exhibit a high diversity, while at the
same time the number of similar tissues was minimized. The dataset
therefore comprises a robust expression matrix across a diverse but
minimally redundant representation of the human anatomy.
In a first step, we performed a Principle Component Analysis to
cluster the samples and identify groups with similar biological
function. The plots for the first three principle components are
Component 1 versus 2
All three plots clearly separate
individual clusters from the remaining tissues. For example, the
central nervous system tissues show a common but very distinctive
profile relative to the other tissue types. In a second step, we
therefore searched for genes that are differentially expressed
between an individual cluster and the remaining tissue types. Here,
we show the example of the CNS cluster versus all other tissue types.
This was performed using the RankProd package of Bioconductor by
comparing these two groups and identifying the most significant
genes. The top 50 genes are listed below.
most differentially expressed genes in the comparison Central
Nervous System versus all other tissues, as calculated with the
RankProd package from Bioconductor. Listed are genes expressed in
CNS but not expressed in other tissues.