Open Access Research

Activity map of the tammar X chromosome shows that marsupial X inactivation is incomplete and escape is stochastic

Shafagh Al Nadaf1*, Paul D Waters12, Edda Koina123, Janine E Deakin12, Kristen S Jordan1 and Jennifer AM Graves12

Author Affiliations

1 Research School of Biology, The Australian National University, Biology Place, Canberra, 0200, Australia

2 ARC Centre of Excellence for Kangaroo Genomics, Research School of Biology, The Australian National University, Biology Place, Canberra, 0200, Australia

3 Current address: Cytogenetics Department, ACT Pathology, The Canberra Hospital, Yamba Drive, Canberra, 2605, Australia

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Genome Biology 2010, 11:R122  doi:10.1186/gb-2010-11-12-r122

Published: 23 December 2010

Additional files

Additional file 1:

Male and female gene expression for 13 ubiquitously expressed genes on the tammar wallaby X chromosome. Genes are presented in the order in which they are located on the X, from the centromere down. No expression was detected for PLP1 in male or female fibroblasts, so this gene was eliminated from the analysis. Expression of these genes in fibroblast cell lines (five males and six females) was normalized to the expression levels of the autosomal housekeeping gene GAPDH. For all but two genes (G6PD and TBC1D25), a higher level of expression was consistently observed in females over that in males. A high variability between individuals was observed that could not be attributed to particular cell lines consistently showing higher or lower expression for all the genes tested. This variability between individuals is thought to reflect differences in the rate of transcription, but could equally well reflect differences in the probability that a locus is transcribed.

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Additional file 2:

RNA-FISH results for two additional females and two males cell lines.

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Additional file 3:

List of primer pairs used for qRT-PCR.

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