▁few ▁years ▁he ▁also ▁collabor ated ▁with ▁Dr ▁David ▁Os cier ▁( a ▁medical ▁consult ant ▁at ▁B ourn em outh ▁Hospital ) ▁on ▁the ▁ha emat ological ▁disease ▁of ▁poly cy tha emia . ▁ ▁Mac lean ▁is ▁best ▁known ▁for ▁his ▁pione ering ▁work ▁on ▁trans gen ic ▁fish , ▁along ▁with ▁his ▁friend ▁and ▁colle ague ▁Zu o yan ▁Z hu . ▁Using ▁rain bow ▁tr out ▁( On cor h yn chus ▁my k iss ), ▁z eb raf ish ▁ ▁( Dan io ▁r er io ) ▁and ▁til ap ia ; ▁he ▁used ▁mole cular ▁methods ▁to ▁study ▁gene ▁reg ulation ▁in ▁fish , ▁and ▁was ▁successful ▁in ▁producing ▁growth - en hanced ▁trans gen ic ▁til ap ia ▁for ▁use ▁in ▁the ▁third ▁world . ▁He ▁also ▁collabor ated ▁with ▁Aqu ag ene ▁in ▁the ▁United ▁States ▁in ▁producing ▁trans gen ic ▁til ap ia ▁express ing ▁human ▁factor ▁VII ▁( a ▁cl ot ting ▁factor ) ▁in ▁their ▁li vers . ▁ ▁Bibli ography ▁ ▁Mac lean , ▁N . ▁( 1 9 7 6 ). ▁Control ▁of ▁Gene ▁Expression . ▁Academ ic ▁Press ▁pp .   3 4 8 ▁ ▁Mac lean , ▁N . ▁( 1 9 7 7 ). ▁The ▁D iffer enti ation ▁of ▁C ells . ▁London : ▁Edward ▁Arnold ▁pp .   2 1 6 ▁ ▁Mac lean , ▁N . ▁( 1 9 7 8 ). ▁Ha em og lo bin . ▁Bio chem ical ▁Education ▁Vol .