r'ebruary 27, 1968

   i"he similarity of i;hcerili:n-t of the  "c:)iitr~iiitig eLe~i~lit" in the
2 and x zm c>l;;es conforms Ath the cCii-;e:; in mLi:'e \~%~r?:r'e di 'ferent
'known nystems ha;rtt t ken 0.1 r cor,trol of gent ~~trtion a i; the & locus.
The tests of this were conducted by v'li-.fc:r :;zlson.    iii) is now
writing up the reaul-ts of tt i.~:rge number 02 tests aimcci aL pi3cement
of sites of chanrre witilin the & locus th;:t 3.:-e responnible for
mutru;t ex;ressi:jns.   frost of the mut-3nts sJere 'tspont.zneousf' in
origin.   A focr woe grodticed by X-rays.   Both multisite and si.n@e
site mutrints are represented among these ~electigns.  In &dition,
five casti3 of chrqie in gene action induced bjr the presence of known
controlliry: elements Ldere i.:icl..:ded in the site rnal;pi.:ig tests.
Une multisite (dfJ&iencpj mutdnt covers a segment within the locus
th:lt is clo.:e to its middle.   The co!;trolling element in ezch of the
five cases lies within this region of the locus.   Three of the five