In conclusion, our results are not consistent with the hypothesis that the over-representation on the X chromosome of genes with a function in brain resulted from relocation or copying of brain function genes from autosomes, either independently or as transposed blocks of independent origin.
By contrast, few progenitor cells (Pxn-negative cells) are observed in lymph glands when single-copy loss-of-function mutations of Pvr and Nup98 (Pvr C2195 / + ; Nup98 Df(3R)mbc-R1 / + ) are combined (M′ ), further indicating the close interaction between these genes.
Since that time, additional high-copy and loss-of-function suppressors (all related to RNAPII transcription) have been identified on an individual gene basis (e.g., Krishnamurthy et al. 2009; Ma et al. 2012; Wilcox et al. 2004; Wu et al. 2003).
First, the redundancy of duplicated gene copies of similar function from different parents (homeologs) may affect the strength of selection.
Such evolutionary events are thought to be the biological basis of the immense plasticity of Brassica species and may have led to a diversification of the genes retained in more than one copy, in terms of function and/or expression.
We find that flies carrying one copy of a loss-of-function mutation in the dFatp gene exhibit increases in triglyceride storage and circulating free FA, with a concurrent reduction in feeding behavior.
This construct was targeted against all mbl isoforms and silenced mbl gene expression by approximately 50%, equivalent to having one copy of the loss-of-function alleles mbl E27 or Df 2R BSC154 (supplementary material Fig. S1).
A copy of MATLAB functions used in this study has been uploaded to GitHub and can be accessed here: https://github.com/tfburns/MATLAB-functions-for-complexity-measures-of-one-dimensional-signals.
Duplicated genes are most likely to be retained in the genome when the two descendant copies partition ancestral subfunctions of the single-copy progenitor or when one or both copies evolve new specializations of function (Lynch and Force 2000; Lynch et al. 2001).
A further discussion of function copying is not necessary for the internal consistency of claims made here.
Because topology copying offers a means of function passing, we propose here that it is a hypothesis worthy of serious consideration.
