From: Re-analysis of the larval testis data on meiotic sex chromosome inactivation revealed evidence for tissue-specific gene expression related to the drosophila X chromosome
(1) X → A retrogenes with testis biased expression 
(2) Under-representation of male/testis-biased genes on the X 
MSCI as driving force (pros/cons)
Down-regulation of testis-specific insertions in the X. Use a single promoter [24, 29].
Down-regulation of X in meiosis. Use mixture of cells .
Down-regulation of X in wild-type testis as opposed to bam mutant testis . bam mutant also show small degree of down regulation .
Complementary expression in meiosis for X → A Retrogene .
Under-representation of male-meiotic expressed genes in the X .
MSCI NOT as driving force (pros/ cons)
No global down regulation of the X chromosome in developing testis . No statistical supporta.
Retrogenes with general female or unbiased expression . No expression data support.
General tissue-specific under-representation on the X . Tissue-specific genes are enriched with testis-biased genesa.