I, P;Qesentcd evidence showing that b.f,b, cgcle results i:' altorations in
heterochronatic elencnts of chromosomes of complement -- contromeres, ends,
knobs and nucleolvs o:ypniL:er.

  2. Because new mutr?ble genes apyca?Jed in pro.yeny of b..f.b cycle :,lants,
the relationship bet!?,reen altered heter ocli_yc-::xi;in s.nr? tl-:ei7 ac3earcmce s
susgectcd.

  3. Eescnted evidence of induction of D-t-ty-,e action in endosperms
undergoixg b.f.b. cycle xhcre al homozggous,

4. Gave reason for expecting dots of Al in sectors -- the sta-i:c of the
"1  recessive:  Produces dots of Al in presence of St.
  5'. liecent work with a E - Dt system.   ChanrFes
sroduce early xut:!ti ns  o Al and to pales.  !ihis in state cf a 1 found:
_.                                 done bg i,juff~r a-t F&ssouri,

  6. ilew :>ositicnn of at found:
                      *Ai3           \

   a).  iihoades:   D-t i.7 his  strain locazed at or $n knob in s1:o-:~t a-.m of
chro-::oso:ze 9.
   3. EUr"fCT,  analysed strsins of maize from South America to see if Dt
might be present i  them.   >'ound D-t unit in two stra:ns:
one from aY2zj.1,                                   Gne fyo1-1 l!e ~72 2-?;,qd

      Both of the se Dt units be%ve just as Dt discove::yod b?; XhoaCes.
Can not be dis5inguished from one anoth r on basis o.:- rcti:.n of  a
      Posj-tic-- ns of ilt units in c:--ro--~so:-le tom-lemcnt:   C-We  5:      not
in chro .c` so -:e                           -/ T                    ana ysed;
        9 but linkage w?.t?~ 1 suc?gest it is .?_oc~~~ixd in c?ro --x---e 5,
    yklis c;cIected, i? Dt like AC.
of the ch7-oncs0-7~e con?lement.        Can hf-.:e it loc~~~?xzd. in earious parts

       Thene 7-h b,,ults brine resemblance of Al-D!
concerning the Ds - AC s:rstsm,   'The          system. cloq~r to tlx i; l:Y`Crrn
                                s 0172 Yi i c  ,egi*e.;Sni;fe- II l"o?lnd in e c i21TT
                                                                           .   .'
sectozials  n e 0 (-z  ,f -de r-2 +- 0 -7  i n7.r 0 s -i, i c ; cl, jy 2 t.- n
   In the a.1 Dt'system of       f 0 -p  s:!.pAi?_T2.ritj.rbq L .
                     j-Q;.0 a:2be s , hidden mutatirlns very much s:~sr,ecf;od
on basis of riis i:rj.'o~.:i-*
            . dL:'n of dots in t:?e kernels -- not random, Lu? in
sectors,


c'ould not be due to double-crossovers;  No recicrocnls:C Sh bz .

   4. ~!hen no AC in hc~L~:~~oz;~go?~s parent, c~ozsed to C sh bz wx Bc,  no
exce-:tional ke::nels found; no c~osso~~crs between Bs and Sh either.

   d). 3us2ected t&t  the exceptional kernels xl th
by chance in action of bh to sh $roz1 Ds event.    7 i3s sh Bz tie e produced

4. The tests of the horiloz~~gotes:

I DsSh f3z AC   or AC
1 23  si-1 bz    ac     ac

x C sh bz m no AC

The results:

parentage in
cross           I Sh       I sh        fICIlSh        11 lf
                                                C   sh     totals
                           e-d- -       -.-.-                      .--P-^*--..---

       P'emale   2,365       16           22      3
Case I                                     21;.@6

       Hale    11,1$!.2     111.2          16       22     11,622

     Fenal e    9,082       1e         55        2
Case  II                                     9,157

     i4al.e     5, oolc      l&         4        2      rc;, o&L&

IV, Tests of the I sh kernels:

12 :rere I Ds 5% bz
             --_

1, The I Ds sh E;z Ire:.-nels:

   a). In 9 of 37 casts, reverse nutzti 71s to Sh occuzaed.
Ds loc?Ltion in the reversions.                       No chaye in
                     'I'wo of 9 hi,g)l:T zm:,able:                     I-

--.-.- -._ _ .  __-. - . . _   _... ,. .-  _.__", 1-s.. U" . . .

        I Dssh  - 1 iIs% - I Dssh
changed in laion, P        D~?O& -removed 76en mutstians occur, no?

        -..... ._     ,.l .

   b).  One 0:' the mut-: ?:les:  CL-ozsing over, g~::a.-tly modified:
50 $ over standard in I to Ds region,                        Il?Ci-%aSed
                            and 300:; OVC:TI standard in dssh  32
region.   This ame7;-zes even when mu.t.a,ticn to Sh OCCUTS.
over tkree generLtl:.ns                            'Tests cp--:dL:.ctc: :
                -- ~310 3 sipaL: oyc-sr renains :-: I&,
                                                                  .-I

    4.  C'ther> ci".ses whore 1~evcx~sio~-,s occur
in rnal-ked rc{:ions : I to sh, and sh to Zz.   -- no chan)se ir, CYOsSbnT o;~cv~

   d). Among the non-?ev&rsion group:
basis of cro r3                   DistSnguished flop one anot'- ::;7 on
           s m .j j2g-over:
sh to Bz            Some s17ow normal amount; soxc shois~ redxctiin in
    intcrval;'-JGe she:: no  cro ssinc; 07er in sh to Dz into- val and
reduced amount in 1 to sh ixlterv:.l.
   4. In all 37 casts of xut:tfon tr sh, normal mle and fe;mle t:n nssni:,siol
and via?;le ho~oz:rgotes,


-3-

   d. In one cc2se - Case II - AC in chro`x~so:*:e 9, to left of I.   In
a. jority 05 tne I Dssh ke:mels, loc?tic>n or stai:.e of Ac was altered coincident1
with a;x?c:.r~nce of mutation,

2, The I 3s sh bz kc.::;rrels    12 ca3r s

   4. i,iarked dil'fcrences etii-bited among ixem:
      Plant from one kernel -- bz; non-mu-?able; no pollen and no kernels
formed.   Comle':ely male and female sterile,
     Lthe s differed with re;Tard to urese`nce or absence 02' reversions;
in viabilities +.en heteros~,~gous and ho!:loz;~cous;  in tl+ansmis.sion:3 t::rol:gh
male and female gametes,

   b). These 11 formed a EradeS. series,
?? ?? ? ?? o  8h and bz phenot::-,es:  Kormal male and i'eriale 'G ranr,mi -, R i-on!: ;
       , r-    to 33?$%t of bz and right of I.
to 132 in pGi:sence--of AC but rate very-low,  Normal hoaoz-gates;   rev sic:l:-
                                MO rev-rsicns te Sh noted,
am?o~~0 s 01 l.e :  normal,   Crossing over I to sh normal;   not tested belxcen
sh and bz.

(2).  Exactly like above,  except that no reversicns o? s:h or bz noted.

    (3).  Reduced transmission of chro:l~sc~;~e carr;:ing the Ds sin bz modified
segment.thrcugh male; no reduction_.through female; homozT,gote vei?' inviable.
Chro:~ soi~e normal;  crossing over I to sh normal
                                    -3

    (b.). Very much. reduced transmissions tlrov& male of chrc:-.;osome
carr;iing I l>s sh bz  segment.   Rormal transnissions tilroug3 female; no
homoz:;gotes; hetarozygotes (1 dose of Ds sh bz segment) very abnormal and
quite inviable iil soye kernels.   G~yc)-.~c~~o~--e roy,:?.al in :Inor~.:l~olog~y-;  crossing
over to eithrr side of modified segment normal; no crossing over r-3-I; in
segment noted.

  CL In all casts, 3s pr::ccnt,
in ceses                 Ds sh bz formed a unit in inh;rit?nce,
     xhe:-e reduced transmissiins occur:

d). 'I'he inviabilities of' the hcte:-.ozygotes -- dominance -- not due to a
deficiency.  Deficlenc>: of whole short arm of one ChTY? oso:-ie -- normal kr.rnels.

   4.  Conclusions:   A Ds event, resulted in chan[;e in action of Sh and Bz
coticidently.   Produced only when AC nresent,   No cl-mye ft.13 loc~:tion t5Z-t
is marked noted.   Reversions in only one case -- Cancl t: his a case of no:;xal
transmissions 2nd via? ilities' of Scmoz:?gote,
                                                  -      Spread of mtitional effect
probably beyond Bz as indic.ated by t'?e inviabilities encountered,
MO chanp;e in chrc-lo:;ol,le morphology noted in any case.


V, The s:Jread 0: change along chrc::oso:ne from Ds to I.

1, The  "C" ko1mel.s in table:   '%ese ex-oected on fol?_otld n,~ reasoning:

%`emale s :

Ds break:

                  One-third of sj1or-t arm elmminated:   'L'L;'cis is not
sufficient def'icienc:: to eliminate functioninp of female gametophyte.
                                                            . >

               In cross:  would expect C Sh`Bz kernels fro?: this and
they shou1.d be v~ariegated for bz due to b.f.b. cycles

  2. On the ears, some of the C kernels sl-icwed exnected bz variegation;
others did not siow tF.is v::riegation,   Some exnectcd not to show b.f.b
cycles:  transloc~:tions, non-recinroc31 could occur occasi nally to
                                            *
produce:

                . . . . . . . . . klBb _
                                      v

3. The anal:Tsis of plants from the two t:,Tees of C kernels:

10 from CBz - C bz variegated c&ass:   All as ex:'ccted:

  Ho Ds present in tests of subsequent generations.
10 from the C I;z, not obviously varie.rated class:

2 -- non-reciprocal translocations: rT'wrt`~- 8     No Ds,

1  -0 Homer dicen.tric,  centromere removed
    from one chrozatid.   No Ds,                 t        F
                                                                -, d,
                                                                c

4.. The remai-ing 7 in the C Bz, not obvi::cslg var. class,
4. All had normal c;';ro.:-o sclnes 9,

  b), All had Ds,  just to left of Sh.

   d. Xvldcd into two classes on basis of $gezetic behaviori
    4 --  Reduced trafis;qli sion of the Sh Ez chr c x7 scze ti>rol;gl-: nn1.e.

      3 -- No trans6ssion o:.' Sh Bz chro "osr_'--:c: th::ol~~% male,
   d); The homozygotes:
::rith C :  mlored kernels.   In 4 cases:  colorless kernels.   The heterozy~otes

                 >      v P-Q-d I` Paw%&


Red I   Ds Sh Bz    Crossing over Red-I to IIIP, -- none.
                                I?          II    Sh to Bz -- normal.

C   ds sh bz

4. The seedlings ProIn the homo_ygotes:   ereen --  albinescent -
      All four cas~:s exactly alike in tl-i-c;se rcsricc`<s.

dies.

   f). The th:?ee remaining cases:  Like above, except no male t:;-ansmi7sions
of chro 10s~) les r;ith the "red, .I".  z'orm good homoz:'gotes with othe:- $ cases,
however.

   .d.  Gonclusic.ns:  Action of I, or a deficiency, not seen, to left Of Ds.
Ds not removed by t::is.   Crossing over in a.ifectc,d se<gment not seen.

VI. Genera.1 conclusions:

1,lGenes close together in this case.   Ds in the mid.?le.

  2. Chanps occur to both ri&t and left of Ds but Ds not removed or markedly
altered in locption :&Len change in genie action occurs.

3. These changes are relatively rare -- see ta'::le -- but metr:ods used will
find them readily.   This not erlsy in casts whore Ds not close to aevoral
loci -- t5.c majority of cases.
4. Analysis reveals spread of mu.?:,ticnal chan~ealong ci~~o::~so~.e.  Not
always deficiency, as t3.e ca c of bz to Bz coincident with s'n bz mu%-tic.n
????? o

5. Deficiencies not probr.bly --
always nl-escnt in these cases.    s'?oul:! lo-e Ds in many c,~sos but Ds

of Ds sh bz not the exnlanation, Also, a heterozp;rous deficiency, in cc.s'-s


  6. Tilese rare c~'.sos can c,xnlain the few cases, in stvd- of c-ml, where
--eversion to c not accompanied b:: loss of Ds,
Also                              It remained verr close to C,
( ED;omz ;e;;e;; thEt, rev rted to mu a-le condition noted -- ana$n, :~arc.
     -          1h1.s CDs gives c-mu-ta'5le aFain,)

The s:-stem controlling evmts at  a
         A / a sts and AC  1Om2

I. PiFst au;3e::rznce:
sin.glc kernel foil05rj.n.r; in culture hn'~i~pS F.
             cross o:? female by al/a 1

2.  Two classes of mu:;ations:
    Class I. -- To hig?:er
smooth over ale.3rone layer. alleles of normal Al
                  Plant: Dark color;

Ghange at Al; folund in

Jie:nel dazak color; color
leaves colored in blade,

     Cl ass II mut.?ti'ns: Very different: Diffuse -mottol2d:   Quantative
exnressions
        L    from nearly
sh&th, glumes,       colorless to very dark.   Plant: color in

dun colored --  but none in the blade except in mid-rib and edge of leaf.
          requires much sun to form dark color:   U? Tl e iq
sides of plumes show t?,is:-                               z-cd 1o:rer

     Mu.t?.tiins or;' hot:;. classes are stable,   MO relation bet?;een color in
kernel in diffuse-mottled class and color pl->oduced in nlttnt by same
mutati n.  An almost colorless kc:>nel ccn ;>rodv.ce plant with dark color.


3. Mutntic  s occur in slants -- can Tecognfze bot:-L ty:es :-e:.,::'ly.
    Plants derived from v.riegated kcmels -- will  s`-1.0w both cl.asses of
mutatii: ns,

4. T-he &em&ml muttItic:ns:  To full Al
All stable in subsequent generations,   and to th.e diffuse mottled cl&ss;

5. The frequency oi' germinal mutations:   Sxamples:
  al-m.Z/al m-2 fezde x a,s/als male

16 ears:     Full Al     diffuse-mottled

105       955

variegated for both
  types of mutanticns.

2751

Total -- 3811

l/4 -- 953.

Xach of the diffuse mottled mutations a new one.

5 ears

~"~11 A 1     diffuse-mottled      variegated for both
                         t>Tes O.-i mutstlcrls~

31        309               579

        total -- 919  l/3  -- 306

4  ears

Full A 1         diffuse-mottled   variegated for both
                           ty7-es of mutants

47          4-J-8             434

      total  - 899   +  -- 449.5

Through male -- often same types of ratios o`oscrved:


.

7. Conclusion:   Some factor present -- scgre<mating at meiosis.   `-Jhen
absent from nucleus,
.>i            a mutatLcn to the diffuse mottled class occurs.
Ihese mutants ati&iLe from tlhen on,
         This factor also s*gregntes somat9c 11y
di.ffuse mottled mut::tZons                           -- consequence, a
                  x3en factor re.moved from the nuc'eus,
          Factors probably move about, as dots AC.     Tj
                                                     lre3son for  4-T
unit ratios observed, w3en'not 1 : 1,                                           de

m--1_--.

        Sgstcm controlling mu%ations at al - ml.
1. kiany different types of mutations Occur.  Xany different st,ates arise,
2. A11 have essentially same spstcm of control of ml.iiSations, but mcc,-t of
study conducted r%!ith one state
mutants            -- that :-roducI.ng dost of Al and some pale
      -- th$se last will .be ,s~~own
encountered,               to be not like mutants previ0::sl.y

.: . The general pattoln of behavior of the controlling s:Tstixrn.
  a). A factor, Pod 3
present&zo,        for variegation,  and modificat?on of action of a
       r vsrieCgation to                               locus,-
                          occur.                                  1

  b). When V present, the kernel color:
   Al and pale areas.           colo:xless backgrol;nd; dots of full

Pr kernels                pr kernels

,!


1


     ,I
. . :                                     `i      .C'

CL Xhen V absent, all kernels are palp non-varie<gated.

?r-kernels

pr ke-nels
      .+-

d) . 'Ihis nhenotqe aUcears
become mutable w3en V added:
to full A$   ATaln,  scme of

genc:>atir:n after gene:;ation as stable.
%en                            Will
the ra$,e color of background -- colorless, mutation
        areas.

  4. The V shows dosages
time of change to ftil Al. -- seen in other sY3tJes very clearly -- co-iltrols
                Somet:;Tng like AC in t-is respect.

d).  Linkq:c of V found -- i3rs-t; ?inka,ye - chro::osoze 6,  Tc:ble on Y-,o:x-d,

  e>.  Sevcpa]. ,yisker --.lal37'"
                                 -LS -- V not

  f>. Some T,lants --  ratios indicate
in same c?1rcxso -e,  hiwG.4, 5,


  d. %e ratios and behaviors suggest that V is transposing, 2uzt as AC
transposes, but these transpositions occur earlgel than those of AC studried.

3. '2he somatic c",anc:es to 'pale" - give rise to ears:   Sectors :

&$. The kczlels with al-ml/ als,/als

Wormal

Y v/ y v /y v:

  Loss of chr.6 in sector

5,s `-
    OlXl -i; 1 C chan-tes in sin,yle plant:

    1 ear on plz3t : 1 : 1 fo- vxr. to nale

    FI.ller ea_n :  3var : 1 pale

     "thsr tille-:  all pale.
6. 4 a3d 6 above suggest sozxtic segrept?cns of V,

--

';ompnrisons Setxeen controlling? : systr:ms of al-ml and al-m2



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