X inactivation presents two longstanding puzzles: the counting and choice of X chromosomes. Here, we consider counting and choice in the context of pairing, both of the X and of the autosomes.

中文翻译：

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配对计数。

X灭活带来了两个长期的难题：X染色体的计数和选择。在这里，我们考虑X和常染色体配对的计数和选择。