subfunctionalization

You could follow the kind of reasoning that Chris Hittinger and Sean Carroll followed when studying subfunctionalization and adaptive conflict in yeast genes.

Behe's Two-Binding-Sites Rule 2008

Neofunktionalisierung but could possibly also run through subfunctionalization He & Zhang, 2005, Rastogi & Liberles 2005.

Flagellum evolution -- how's your German? - The Panda's Thumb 2010

Zhang 2005 Rapid subfunctionalization accompanied by prolonged and substantial neofunctionalization in duplicate gene evolution.

Flagellum evolution -- how's your German? - The Panda's Thumb 2010

In more recent work is the emergence of a new position in duplicate also called Neofunktionalisierung eg Beisswanger & Stephan, 2008, Teshima and Innan 2008. gene duplications are frequently observed events, but it is relatively likely that as a result of either a functionless pseudogene arises or that a subfunctionalization begins.

Flagellum evolution -- how's your German? - The Panda's Thumb 2010

Liu RZ, Sharma MK, Sun Q, Thisse C, Thisse B, et al. (2005) Retention of the duplicated cellular retinoic acid-binding protein 1 genes (crabp1a and crabp1b) in the zebrafish genome by subfunctionalization of tissue-specific expression.

PLoS ONE Alerts: New Articles Gayathri Chandrasekar et al. 2010

Preferential co-expression of different subsets of Egfr ligands corroborates the possible subfunctionalization and specialization of the two receptors in adult tissues.

BioMed Central - Latest articles 2010

Preferential co-expression of different subsets of Egfr ligands corroborates the possible subfunctionalization and specialization of the two receptors in adult tissues.

BioMed Central - Latest articles Juliette Laisney 2010

Lynch M, Force A (2000) The probability of duplicate gene preservation by subfunctionalization.

Citizendium, the Citizens' Compendium - Recent changes [en] 2009

K, et al. (2006) Evolution of the cichlid visual palette through ontogenetic subfunctionalization of the opsin gene arrays.

PLoS Biology: New Articles Christopher M. Hofmann et al. 2009

It has been suggested that, after evaluation of MADS box genes 'phylogenetic and expression analysis, subfunctionalization and/or neofunctionalization play a role in the maintenance of most of the duplicated regulatory genes in Arabidopsis

PLoS ONE Alerts: New Articles Elisson A. C. Romanel et al. 2009