7830

• UCREFRP Catalog Number: 7830
• Author: Dowling, T. E. and B. D. DeMarais
• Title: Evolutionary significance of introgressive hybridization in cyprinid fishes
• USFW Year: 1993
• USFW - Doc Type: Nature
• Copyright Material: YES

_ ...t1"TERS TO NATURE
TABlE 1 Frequencies of diagnostic alleles
Allopatric populations Isolated populations Sympatric populations
Locus Allele G atraria G cypha G elegans G robusta G seminuda G jordani upper LCR Green R upper Colorado R.
M.Aat-A a 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
b 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
(33) (20) (20) (69) (43) (20) (21) (40) (55)
All-A a 0.00 0.55 0.00 0.00 0.32 O.SO 0.00 0.26 0.73
b 1.00 0.20 1.00 1.00 0.67 O.SO 1.00 0.36 0.24
c 0.00 0.10 0.00 0.00 0.01 0.00 0.00 0.35 0.03
d 0.00 0.15 0.00 0.00 0.00 0.00 0.00 0.03 0.00
(33) (20) (20) (69) (38) (20) (21) (SO) (55)
Cbp-l a 1.00 0.25 0.00 0.96 0.43 1.00 1.00 0.00 0.00
b 0.00 0.75 1.00 0.04 0.57 0.00 0.00 1.00 1.00
(33) (20) (20) (69) (43) (20) (21) (SO) (55)
Ck-A a 1.00 0.33 0.00 1.00 0.51 1.00 0.90 0.44 0.37
b 0.00 0.67 1.00 0.00 0.49 0.00 0.10 0.56 0.63
(33) (20) (20) (69) (43) (20) (21) (SO) (55)
Pgm-A a 0.00 0.00 0.58 0.29 0.20 0.00 0.00 0.00 0.02
b 0.02 1.00 0.48 0.71 0.80 1.00 1.00 1.00 0.98
c 0.98 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
(33) (20) (20) (69) (43) (20) (21) (45) (55)
mtDNA 'atraria' 'cypha' 'elegans' 'robusta' 'elegans' 'cypha' 'cypha' 'cypha' 'cypha'
(5) (5) (4) (16) (24) (4) (3) (7) (2)

Sample sizes (in parentheses) and distribution of diagnostic allozyme alleles and mtDNA haplotypes from Gila populations examined for evidence of
introgression. Diagnostic allozyme markers were discovered in a SlJ(Vey of 28 presumptive loci (described in Fig. 1). Alleles are designated by ascending
mobility, with 'a' most cathodal; locus nomenclature follows ref. 29. mtONA haplotypes were identified by digestio'l with a minimum of two restriction
enzymes found diagnostic for these taxa. Locality information provided in Fig. 1. Some categories are represented by several populations: 'allopatriC G atraria'
were obtained from the Sevier and Bear Lake drainages; 'aJlopatric G robusta' were 58/Tlpled from the Bill Williams. Gila. Salt and Verde rivers; sympatric
populations from the 'Green R: sample were morphologically identified G robusta from the Green. Yampa and little Snake rivers while 'upper Colorado R:
represents similar specimens from Gunnison River and DeBeque Canyon and Rifle areas of the Colorado River; and G seminuc1a are from the Virgin and
Moapa rivers.

in~icale~t zoologists ~USl de:. the same~ ~n addition" by~djt-
alton amons tbese CriuealJy etldanseredtaxa has been cdn.
sidered primarily as a detrimental" anthropogenic phenomenon'"
but the apparently pervasive influence ornatanl introgression
suggests that consematioa stratqies should evaluate the impact
of hybridization in a new light. 0

Received 13......- 1992: .xepted 27 Janu8ry 1993.

1. Anderson. E. t""'Cressn.. HytJrldz_ (W~ey. _ YClII<. 19411.
2. Gt..t. v. PI""r SpeciMion 2ncl em (Columbia Univ. """'.. _ YClII<. 19811.
3. Harrison. R. G. in ()Jlfon/ s.....rs in E.olulionMy BioIocr Vol. 7 (eels Fuluyma. D. & "'ntonovw:..
J.l69-128 (Oxford lWverSiIy Pre... New YOlk. 19901.
4. Mayr.E.l963. AnimalSpecies_EwoIulion (!letknap. Harvardl.l1iversity Press.CIII1lbridge. 19631
5 le-'lin. R. C. & Bitch. L C. EWJlulion 20. 315-336119661.
6. Short.t.. L A1n M:l Bot Gdn st. 447-453 (19721.
7. lee. D. S. er III (eelsl Alias of Norrh American FreShwater Fishes (NC Slate Mus. Nat. Host.
RaleiCh. 19801.
8. Smith. G. R.. Miller. R. R & Sable. W. D. Proc. Firsr Conf. Sci Res. Hat. _. 1. 613-623 (19791
9. Rinne. J. N. Wasmann J BioI. 34.65-107 (19761.
10. Oou&Ja.. M. E.. Min,jdey. W. l. & Tyus. H. M. Copeia 1989. 653-667119891.
11 Smith. G. R rr_ BonnewiIIe ClttJpler Am Fish Soc. 1!IU. 1--8119831.
17. HoIdeI\ P. B. & Sial_e<. C. B. ~ 1170. 409-4:20 119701
13. lleMar.... 8.0.. Oowlin&. T. E.. OclugIas. M. E. Minddey.W.l. & Marsh. P. C. Prcc. naln Acacl. Sa
US.A. 119. 7747-2752 (19921
14. ~s. C. l. & Miller. R. R. __ lniv. U1a/1 38. BioI. 5tH. 10. 17 -144119481.
15 Wolle. E W ,n LarwJsi:_of AriZ""" leels Smiley. T. Nalion.. J..Pewe. T. & Schate<. Jlll1.136
(UnWeJsily Ptess Amefa. New YOlk. 1984).
16. Smith. G. R. Syst BioI. 41. 41-S7 119921.
17. $;C1er. W. F. & Miller. R. R. Fishes of U1a/1lUT St Dept. Fish & Game. Salt lake Cily. 1963).
18. 1tAlbs. C.t... Millet. R. R. & 1tAlbs. L C. Mem Calif. Acad Sci 7, 1-759119741.
19. Miller. R. R. C<JrJeia D45, 104-110 (19451.
:20. Minddey. w.t... Hendridlson. D. .... & Boncl. C. E. in TIle Z_raptry of NtKItI American Freshwaler
Fishes (eels Hocutt C. H. & Wiley. E. 0.) 519-613 (Wiley. _ YClII<. 19861.
21. NeiCe!. J. E. & ..._. J. C. In EWJlutionMy~ses _ Therxy (eds New. E. & Kartin. S.) 515-534
(Ac-...c. _ YOlk. 19861.
n. Pamilo. P. & Nei. M. MoIec. biDf. EvoI. 5, 568-583 (19881.
23. Oowftnc. T. E. & Brown. W. M. Syst ZOO/. .. 176-143 (19891.
24. Fe!senslein. J. EWJlulion 39, 783-791 (19851.
75. Winograd. I. J. el aI. Science 2M, 255-260 119921.
76. ....eIrDO. 0.1. Calif. Acad. Sa Qx: l'ap.132, 1-74 (1979).
27. Arnold. M. L A. Rev. ecoI. Syst Z3, 237-761(1992).
28. Rie_1- l. H. & Brunsleld. S. In PI_ MoIecuIM Syslemalics (eels Solli.. D. E.. Solti.. P. S. &
Doyle. J. J.) 151-176 (Chapman and HIIII. New YorI<. 19921.
29. Shaklee. J. 8.. "'Ilendorf. F. W.. MorilOt. D. C. & Whitl. G. S. rrans. Am. Fish Sac. UI, 2-15 (19901
30 Swofford. 0 L & Selander. R 8 J Metea 72, 781- 283 (19811

446

31. Net. M. aer..IICS .. 583-590 /19781.
32. Murphy. R. M.. Sile.. J. w. Jt. IlulII. D. G. & Haul.... C. H. in Molecular Sys_lies leds Hi">$.
D. M. & Morill. C.! 45-176 (Sinauer. ~ M.... 19901.
33. Swofford. D. & _. S. H. Syst ZccI. .. 293-325 (19871
34. Net. M.. StepnetlS. J. C. & Sailou. N. __ 1lioI. EWJI. Z. 66-85 119851
35. Nei. M. & T......a. F. aer..lics 105. 207-217 119831.
36. llowfinC. T. E. Morill. C. & P_. J. D. in Molecular SySlema,lCs (eels Hilli.. D. M & MonIZ. C ,
250-317 (5inauer. SuncIerI-. MA. 19901.
37. Swofford.D. L PlrykJgenelicAttaly$isIJsilWPBrSimorty. _..",J.(/QII.. Natltst. Surv..OIamI>atCI\
19901.

"'Cl\NOWlEDGOIENTS We _ .... DeMarais. M. E. Oou&1as. B l. .le>'sen. P. C. Mwsh. C. Karo.
W l. Minc:ldey. W. C. Starnes. R. Tommons III1d H. M. Tyus ror assoSlarw:e in ~ specjmen.1II1<I
M. E. CJou&Ias. P. C. Marsh. W. L IAnc:l<Iey III1d G. R. 5nulh lor tfit>t'5m. FieIG -">ition or Iistetl
rishe. was perm;llecl by US Fish l1l1<I Wiklire Service and comparable .tate ..thoriZ.lions .$SUeclIO
one or more of the abOYe-aelonowtedlecl inclividuaI.. Thi. _ was SWflOf\ed by the National ScienCe
Foundalion l1l1<I _tiCalor Incentive "'wards rrom "'rizona Slate I,JniverSity (to T .E.D') l1l1<I runclS
trom US Fish and Wildlife Service 110 T.E.D.. BD.D and W L Mino1<levl

Agrobacterium conjugation
and gene regulation by
N-acyl-L-homoserine lactones

lianhui Zhang., Peter J. Murphy., Alen Kerr.
& Max E. Tatet:l:

Departments of · Crop Protection and t Plant Science.
Waite AgricUltural Research Institute. The University of Adelaide.
Glen Osmond. South Australia. Australia 5064

CONJUGAL opines secreted by crown gall tumours induce strains
of Agrobacter;um tumefaciells that are donors of Ti plasm ids to
produce a diffusible conjugation factor'. This enhances the
conjugal transfer efficiency of the Ti plasmid in other strains of
A. tumefaciells. This factor behaves as a secondary messenger,

! 10 whom cotresponc;lence should be addressed.

NATURE VOL 362 1 APRil:.,?93