seminar, Cornell University, March 2 1971
EXPANDING CONCEPTS IN GeNs?PICS.

I. IN?HODUCTIUL.

1. Periods in genetics, changes in concepts: Mendelian inheritance,
genes and chromosomes; period of cytogenetics; beginnings of biochdmical
genetics; microbiology + molecular biology, bacteria and phage.

Present: period of transition; from microorganisms to eukaryotic
orgunisms. Reassesment of concepts based on increased knowledge of
eukaryotic organisms, degrees of complexity, failures of some comcepts
from microbiology when applied to higher orzanisms. Kuphoria of
early sixties gone: evening at Demerec home, 1963 symposium. Effect:
Gunther Stent, Bentley Glass: all is over with respect to principies.

2. Prediction: studies of eukaryotic organisms, from all points-of-view
will produce very great change in concepts regarding: nature of "mutationd
nature of evolutionary processes; the nature of progr mming mechanisms
during development; the nature of homeostatic mechanisms; the vast amount

of symbiosis at all levels of organi,ation-- the oneness of nature in
general.

3. The legacy from microbial-molecular biology:

The Central Dogma: DNA-RNA-Protein (Already broken down.)

Organization of DNA: operons, cistrons, operator, regulators,
DNA of stop and start signals;

Reading of DNA: Strands and directions, linear.

Ribosomes, transfer RNA, ribosomal RNA,

Replicons; Membranes; sites on membranes;

Repair mechanisms; exchange mechanisms; ligases; nucleases
Mutations from base changes; Supressors and tRNAs

Trinsformativn; transductios; lysogeny; plasmids;
self-assembly mechanisms.

4, Control systems: Complex, even in the microorg nisms. Far more
complex in the eukaryotic org nisms. Regurdless, legacy from molecular
biology of microorg nisms is vast and directing.

5. Eukaryotic organisms: Mechanisms discovered in microorganisms
apply but other integrating mechanisms wxa@e expand and confound the
experimental proceedures aiming at direct comparisons.

hukaryotic organisms: DNA is subject to large amoints of manipulation
in many orgunisms. Increases, decreases, transpositions, vurious types
of organizations and reorganizations. Nearly any tye or manipulation
imagined could probably be found to occur in some organism.

Orzanisms with greatest breadth of experimentation ~- not the
vertebrates, they are relatively dull. Should look to the invertebrates
for exumpies of vastly different types of manipulation: Protozoans,
insects, known to have many changes during development.

The vertebrates: Many interesting types of manipulation of genome;
that occurring in one group usually applies to other groups.

Plants: sess gross manipulations of genome; programming less tight.
Range in products made= extraordiniry in kinds produced. Interrel-iti nship-
with other organisus:symbiosis at a distance in flower patterns, some
products made by plants.
Il. THE BRPECy OF RECuNT INVESTIGATIUNS ON CONCEPTS: A LIST (only)

 

1. The composition of DNA in eukaryotic organisms: Repetitious
DNA; satellite DNAs, total amount of DNA and relation to
repetitious DNA; rDNA, tDNA.

2. Inconstauncy of DNA composition in different types of cells:
Increases and decreases of purts of genome, from small
to large components.

3. Types of metabolic DNA: derived from parts of the genome.

4, Homeostatic mechanisms arrangeing amounts and pocations of DNa
within cells.

5. Different ways that eukaryotic organisms solve one kind of problem.
6. Symbiotic relationships involving DNAs of different origins.

7. The nature of programming mechanisms: sequences of "determination"
events in development.

8. Most IMrOnvawi: Recognition of custitution of eukuryotic cells:
Mitochondria, chloroplasts; organization of cilia, flagella,
centrioles; microtubules; origins of membranes; organization
of components of chromosomes: replicons; rings; nature of
true heterochromatin;

Bukaryotic cell: made up of a number of different parts that
initially were much alike: Symbiotic soup.

9. Tempted to consider evolution by consolidation of individual
components. Must consider possibility of origin of sone individual
components--bacteria; phage; viruses~-as escapes from more complex

organizations. At present time, viruses are gsxm posing this problem in
a most definite manner. We may find more instances for reco sidering
evolutionary mechanisms -- away from the sivgle mechanism of base pair
changes.

Ill. SUONH BexativuwsS OF SYMBIOSIS AT THe LEVEL Or DNA,

1. Bacteria: bysogeny; plasmids.” Yuu) - Cans RP abe

2. Bacteria: transductions; transformations; significance.
Attempts with eukaryotic organisms: Mostly negative in early
studies. Szbalski, “awa and Caspari; Fox.

4%. Brussels meeting; late august, early September: I[nvORPUnATIUON OF
IN#ORMATIiUNAL MACROMOLSCULES. Ledouc with bacteria and
plants, sponsor. Results of symposium:

aw

~
‘

¢ lieupoousy - oalle

= dhe pafon of Mo
ow Cu, gid me PM. athe Bat - Ror

“
%. Time for conference ripe: reason, the studies of animal viruses
in tissue cultures.

DNA viruses into chromosomes; transformation event.
RNA viruses - DNA - (into chromoso..es?)
Coats of RNA viruses: part of membrune of cell, slightly altered.

Are viruses escaped DNA using sites on membranes for coats?

Do they introduce DNA from one organism to another?

Are they present in nuclei of most if not all eukuryotic org unisms?
Hubner - Todaro hypothesis; Dept. of bmpryology addition to th

IV, THs STRANGS UASE OF SaTsLLITE DNAs.
-1. The composition of DNAs. Differences seen at pachytene stage of

meiosuas:
Organization types: SLIDES

 

2. The distribution of "heterochromatin": Species of Nicotiana:
STauming propaitia - (Ructhansr — Lom parotid olifjowiesr alloug tri Riguve
The races of maize: no knobs, knobs, sizes, content of knobs;
metabolic DNAS. 3LLDES

3, Satellite DNA: Initial case, Mouse DNA. SLIDE yy .
Location of satellite DNA: Adjacent to centromere regions. Ww IL

Repetitious DNA and Satellite DNA - relation of mouse to rat.

Unigue presence of mouse Satellite DNA.

4, Other sutellite DNAs: Walker, etc.

(1 Spoedig Wate

2) Gorter dtubdled - ATT TO tral
= Ue taf! odceee
Cdlabad « | i?
q

5. Most extraordinary study of sateilite DNA and distributions: spa Ot
Drosophila hydei; neohydei, pseudoneohydei. ot 2
Tests of satellite DNAs: making RNA from di:ferent isolates;
annealing with salivary gland chromoso:es; locations
of sateliite DNAs found. Se E a
The relation of Dros. neohydei to pseudoneohydei. Kydd {2h li ts

The significance of this knowledge: Incorporation of unique
sequences of DNA and their transpositions to varias locations.
What is origin of these unique sequences? Foreigh?

6. The distributions of A-T-A-f satellite DNAs fxm among crab
genera and species: Relation to knobs and races of maize?

7. The problem: wre there classes of satellite DNAs? Do they have
different origins? Can many or them represent symbiotic conditions
initially? Not impossible: the intrqnuclear bacteria in Paramoecium

SLIDE,

Parasites within p»rasites: Preer. Slide

 

 
~4uo

8. The conclusion: GENERAL PLOW OF GeNe TIC INFORMATION FROM ONE
ORGaNISM TO ANOTHER. COuuD ReSULT IN MARKED CHANGES IN
DNA CUNT#NT AND ACTIONS ITP INCGuvSlOAS AND REPLACEMENTS
Wikis COMPATIBLE,

V. HOMEOSTATIC MeCHANISMS INVOLVING CUMYUNANTS OF DNA: BAAMPLE, rDNA.

1, Qocytes of Xenopus, Triturus; multiple nucleoli; released from
nucleolus org :nizer; formation of many nucleoli = ribosomes in
cytoplasm. Very much publicised. Other similar cases: insects.

2. Oocytes of Tailed Frog: 8 nuclei; similar patterns; loss of 7.
3. Oocytes: Drosophila : 16 cells, 15 murse: i oocyte; RBA productions.

4, Vocytes, Byncosciara: One oocyte; one nurse cell; DNA of nurse

ye _ cell: sequence of events:
naa Ceide ty ia) ~ E aif - % a}

5. The nucleolus orgunizer: Maize and Chirdnomous: Multiple;

control of amount of action: multiple "operators" but control
of which is active; Types in maize: SLIDE

rh. Nucleglus organizer in Drosophila: Suggests only one operator.
Extraordinary homeostatic events:

Bobbed cases: | . + wie
PA your ‘ pal} Abit Yo Uh ents “y t Tinks Likef

i

ay wd dy oh

j Wit aad
KX, XY, XO —- XX. Change in rDNA cistrons with co::trols. cue OM

b. Nucleolus organizers: birds; microchromosomes: SLIDE

 

VI. HOMEUSTATIC MaeCHANISMS INVOLVING COMPONENTS OF DNA: Replicon increases,

 

1. Specific bands in salivary gland chromosomes of Chronomous:
Vont.nuous DNA replication and release, as no accumulation.
Wndtabswc ONA~ many mardi willy Weta = P G

2. Specific bands in dSciara group, Chironomous as seen in salivaries:
1-2-4- 8-16. Not released but continuous in chromosome.
3. Relation of this mechanism to evolution of some families:

Ranunculacele: Metaphase chrumosomes: SLIDE
DNA content: 1-2-4- 8-16 Ris and Kubai.
VII, HOMEOSTATIC MeCHANISMS INVOLVING LOSSES OF DNA: Heterochromatin
losses: soma vs germ tine:

1. Ascaris; Yopepods; elimination of heterochromatin.

2. Extreme cases: #Hlimination chromosomes in Cecidomyids:
4ygote: 4 + 4 soma chromosories + 30 or more Llimination chromosome:
Germline, retains E chromosomes; soma loses all « chromoso es.

Action of HE chromoso:es: take over functions of organizing the
gonads and germ cells. “oma chromosomes appear to be
inactive. Fantastic controls evident by organization and
behuvior of two types of chromosomes in development of oocyte.

Illustrite extreme case of separation of programming of chromo-
some sets.

( I af) ag
VIII, THB _SIGNIFIC.NCe OF TRUE HUT ROUHK WI ATIN, saldile DitRs

 

 

IX, CONCLUSLONS: New concepts must incorporate knowledge of:

1. Symbiosis: related to organizations in past evolution
produces exchanges between genomes at all levels of
orginizations.

2. Manipulations of DNA: part of the developmental and the
evolutionary events resvonsible for action of present day
orginisms. All types of mantipulation known among different
groups of organisms. Only a few cases could be mentioned here:
Others extraordi:ary: “‘acronuclear arlaga of some protozoans.

Vontrolled non-disjunctions; Controlled transpositions;

Various aspects of "metabolic DNA". Controlled endomitoses:
set from one pirent only; other not replic ted.

Many other instances of maniphlation.

3. Programming of the genome: not considered in this talk, but basic “>
changes in organization of DNA during development, involving
components of gene locus: locus is large to accomodate changes. \&

Ve

4, svolutionary mechanisms: much more than mutations through base-pair
substitutions. s4tnvolve the above three basic actias.

e. dhe mature aati 4) Tous howohomny a

ike pe
Any organism can make any other organism. tnzymes much alike; they are
only the tools, putting together and taking apart where ener; y and speed
required. °
SLIDES

(¥ neaicareo murex (2n= 16). Fachytene, several chrumosomes.

(ee
3,

aD

Yalvia, pachytene stage
Bermuda grass " "
Sorghum " "
tomato tt "

“aize " "

" Feulgen " " B chromosome biv-lent

| 8. wuinacrine mustard fluorescent staining. Casperson, original paper
(FY Amounts of DNA per haploid complement. Table from Ris and Kubai

1Q.
ll.
12.

13.

14.
15.

16.
17.

Diagram Mouse DNA. UOriginal
Mouse Sat. DNA location (gross) Metaphase chro .osones. fardue and Gall
H? synthetic main band RNa from Drosophila neohy.on denatured
salivary gind chronosones of Dros. neohydei/hydei
Jrosophila melanogaster: ectopic pairing. “aufmann and lddles, 1965.

3 from heavy akx satellite DNA of Dros. neohydei(Ectopic regi ns)
H~ synthetic,RNA,timding to denatured saliv:ry chrs. of Dros neohydei.,

" tt wot u t u tt " of Dros.

pseudoneohydei. (Pattern general; about same as with neohydei)

Ranunculaceae* genera. fHleta;hase chrorosomes

DNA content of chromosomes from different organisms: Ris and Kubi