The first thing that screamed at me when reading your code is that this:

sub mergeSort( \@arrayRef ) {

[download]

Isn't a legal Perl construct. And sure enough, running a syntax check on your code exactly as posted produces:

C:\test>perl -c junk92.pl
Illegal character in prototype for main::mergeSort : \@arrayRef at jun
+k92.pl line 27.
Scalar value @leftSide[$i] better written as $leftSide[$i] at junk92.p
+l line 40.
Scalar value @leftSide[$i] better written as $leftSide[$i] at junk92.p
+l line 41.
Scalar value @rightSide[$i - $middle] better written as $rightSide[$i 
+- $middle] at junk92.pl line 47.
Scalar value @rightSide[$i - $middle] better written as $rightSide[$i 
+- $middle] at junk92.pl line 48.
Prototype mismatch: sub main::mergeSort (\@) vs (\@arrayRef) at junk92
+.pl line 55.
Scalar value @groupA[$i] better written as $groupA[$i] at junk92.pl li
+ne 62.
Scalar value @groupB[$j] better written as $groupB[$j] at junk92.pl li
+ne 62.
Scalar value @groupA[$i] better written as $groupA[$i] at junk92.pl li
+ne 63.
Scalar value @groupB[$j] better written as $groupB[$j] at junk92.pl li
+ne 67.
Scalar value @groupA[$i] better written as $groupA[$i] at junk92.pl li
+ne 73.
Scalar value @groupB[$j] better written as $groupB[$j] at junk92.pl li
+ne 78.
junk92.pl syntax OK

[download]

Which means you've either been ignoring the messages; or you added strict and warnings for posting.

Fix that lot, then come back and someone will explain to you why this will never work:

    my ( @groupA, @groupB, $dataRef ) = @_;

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In reply to Re: Dereferencing arrays by BrowserUk
in thread <SOLVED>Dereferencing arrays by divitto

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