Table 2

Controversies regarding meiotic sex chromosome inactivation (MSCI) and the chromosomal distribution of male-biased genes in Drosophila

MSCI

(1) X → A retrogenes with testis biased expression [2]

(2) Under-representation of male/testis-biased genes on the X [1]


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
[25].

Down-regulation of X in wild-type testis as opposed to bam mutant testis [38].

    bam mutant also show small degree of down regulation
[31].

Complementary expression in meiosis for X → A Retrogene [25].

Under-representation of male-meiotic expressed genes in the X [25].

MSCI NOT as driving force (pros/

    cons
)

No global down regulation of the X chromosome in developing testis [32].

    No statistical support
a.

Retrogenes with general female or unbiased expression [43].

    No expression data support.

General tissue-specific under-representation on the X [32].

    Tissue-specific genes are enriched with testis-biased genes
a.


aShown in the current work.

Supportive (pros) or conflicting

    (cons)
data related to MSCI and its role on the chromosomal distribution of male-biased genes proposed through two observations: (1) X → A retrogenes with testis biased expression; (2) Under-representation of male/testis-biased genes on the X. Details on our findings of no expression data support for female-biased or unbiased expression of the retrogenes are presented in Vibranovski, Zhang, Kemkemer, Lopes, Karr and Long: Segmental dataset and whole body expression data do not support the hypothesis that non-random movement is an intrinsic property of Drosophila retrogenes, submitted.

Vibranovski et al. BMC Biology 2012 10:49   doi:10.1186/1741-7007-10-49

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