Coding sequences of genes have a certain degree of evolutionary conservation, so that comparisons based on sequences (BLAST, HMMER etc) can be informative. Generally speaking, the more two species are phylogenetically close to each other, the more their genes will be similar to each other. To add to that, different genes will have different degrees of sequence conservation - for instance, histons are very conserved and so on.
Do these considerations hold true for untranslated regions of genes (both 5' and 3')? To what extent can an alignment of UTRs be meaningful? Are there any very conserved UTRs as there are very conserved CDS? I know that there are some conserved motifs in 5' and 3'UTRs, but what about the overall sequence?