diff --git a/.gitignore b/.gitignore
index 3013702ceedb0579fec7018f87d4a724476ecd4c..3e224c11f6e929cf3d9ed07eda65eb1b5a8eb637 100755
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 # Created by .gitignore support plugin (hsz.mobi)
 .idea
+*.iml
diff --git a/dge_workflow/star_align.kts b/dge_workflow/star_align.kts
index acb9fa162babd1f251de281bb12ceaad954fce21..5d1bdd6ed661851526c51a3022b57f4f09091b09 100755
--- a/dge_workflow/star_align.kts
+++ b/dge_workflow/star_align.kts
@@ -73,6 +73,11 @@ fastqFiles.filter { !it.isFile }.let {
     require(it.isEmpty()) { "Some fastq files do not exist  ${it.map { it.absoluteFile }.joinToString(", ")}" }
 }
 
+require(fastqFiles.filter { it.name.contains("_2.fastq") }.isEmpty()){
+    """Mapping 2nd mate alone is unlikely to have meaningful semantics.
+     Just provide _1 and star_align.kts will pick up corresponding _2 for PE alignment if present"""
+}
+
 println("Running STAR using igenome '${igenome}' for the following files:\n ${fastqFiles.joinToString("\n")}")
 
 val jl = JobList(".starjobs").apply { reset() }