Reader TTS

ABSTRACT Ninety populations of _Daphnia pulex_ from sites throughout the UK and Scandinavia were assayed for genetic variation at 11 variable enzyme loci. A latitudinally-related cline in

both breeding system and ploidy level was observed. Southern populations (latitudes 52–59°N) comprised only diploid cyclic parthenogens. Northern populations (latitudes 68–71°N) were

dominated by polyploid obligate parthenogens and diploid cyclic parthenogens were absent. An assemblage of populations from a site of intermediate latitude (61°N) included both diploid

cyclic parthenogens and diploid obligate parthenogens. This cline parallels one previously described from temperate to arctic North America. The obligately parthenogenetic (asexual) clones

were generally heterozygous at one or more loci for a common _D. pulex_ allele plus an allele not found in cyclically parthenogenetic (sexual) populations of _D. pulex_: it is argued that

these asexual clones arose polyphyletically following several independent hybridizations between _D. pulex_ and an unrecognized but closely related taxon. Fifteen different asexual clones

were detected and 25 of 28 asexual populations were uniclonal: the mean number of asexual clones per population was 1.21. SIMILAR CONTENT BEING VIEWED BY OTHERS REPRODUCTIVE STRATEGIES AND

THEIR CONSEQUENCES FOR DIVERGENCE, GENE FLOW, AND GENETIC DIVERSITY IN THREE TAXA OF _CLARKIA_ Article 12 September 2023 SEASONAL CHANGES IN RECOMBINATION CHARACTERISTICS IN A NATURAL

POPULATION OF _DROSOPHILA MELANOGASTER_ Article 23 June 2021 MATING SYSTEM EVOLUTION AND GENETIC STRUCTURE OF DIPLOID SEXUAL POPULATIONS OF _CYRTOMIUM FALCATUM_ IN JAPAN Article Open access

04 February 2021 ARTICLE PDF REFERENCES * Beaton, M J, and Hebert, P D N. 1988. Geographical parthenogenesis and polyploidy in _Daphnia pulex_ Leydig. _Am Nat_, 132, 837–845. Article  Google

Scholar  * Beaton, M J, and Hebert, P D N. 1990. Miniature genomes and endopolyploidy in cladoceran crustaceans. _Genome_, 32, 1048–1053. Article  Google Scholar  * Beaton, R A. 1957.

_Parthenogenesis and Polyploidy in Mammalian Development_. Cambridge Monographs in Experimental Biology, no. 7. Cambridge University Press, Cambridge. Google Scholar  * Bell, G. 1982. _The

Masterpiece of Nature: the Evolution and Genetics of Sexuality_. Croom Helm, London. Google Scholar  * Cavalier-Smith, T. 1978. Nuclear volume control by nucleoskeletal DNA, selection for

cell volume and cell growth rate, and the solution of the DNA c-value paradox. _Cell Sci_, 34, 247–278. CAS  Google Scholar  * Crease, T J, Stanton, D J, and Hebert, P D N. 1989.

Polyphyletic origins of asexuality in _Daphnia pulex_. II. Mitochondrial DNA variation. _Evolution_, 43, 1016–1026. Google Scholar  * Glesener, R R, and Tilman, D. 1978. Sexuality and the

components of environmental uncertainty: clues from geographic parthenogenesis in terrestrial animals. _Am Nat_, 112, 659–673. Article  Google Scholar  * Hebert, P D N, and Beaton, M J.

1989. _Methodologies for Allozyme Analysis using Cellulose Acetate Electrophoresis_. Helena Labs, Beaumont, Texas. Google Scholar  * Hebert, P D N, Beaton, M J, Schwartz, S S, and Stanton, D

J. 1989a. Polyphyletic origins of asexuality in _Daphnia pulex_. I. Breeding system variation and levels of clonal diversity. _Evolution_, 43, 1004–1015. Google Scholar  * Hebert, P D N,

Schwartz, S S, and Hrbacek, J. 1989b. Patterns of genotypic diversity in Czechoslovakian _Daphnia_. _Heredity_, 62, 207–216. Article  Google Scholar  * Hebert, P D N, Schwartz, S S, Ward, R

D, and Finston, T L. 1993. Macrogeographic patterns of breeding system diversity in the _Daphnia pulex_ group. I. Breeding systems of Canadian populations. _Heredity_, 70, 148–161. Article 

Google Scholar  * Hebert, P D N, Ward, R D, and Weider, L J. 1988. Clonal diversity patterns and breeding system variation in _Daphnia pulex_, an asexual-sexual complex. _Evolution_, 42,

1024–1035. Article  Google Scholar  * Hobaek, A, Weider, L J, and Wolf, H G. 1993. Ecological genetics of Norwegian _Daphnia_. III. Clonal richness in an arctic apomictic complex.

_Heredity_, 71, 323–330. Article  Google Scholar  * Hughes, R N. 1989. _A Functional Biology of Clonal Animals_. Chapman and Hall, London. Google Scholar  * Innes, D J, and Hebert, P D N.

1988. The origin and genetic basis of obligate parthenogenesis in _Daphnia pulex_. _Evolution_, 42, 1024–1035. Article  Google Scholar  * Lewis, W H. (ed.) 1980. _Polyploidy: Biological

Relevance_, vol. 13. Basic Life Sciences, Plenum Press, New York. Book  Google Scholar  * Lokki, J. 1976. Genetic polymorphism and evolution in parthenogenetic animals. VIII. Heterozygosity

in relation to polyploidy. _Hereditas_, 83, 65–72. Article  CAS  Google Scholar  * Lynch, M. 1983. Ecological genetics of _Daphnia pulex_. _Evolution_, 37, 358–374. Article  Google Scholar 

* Maynard Smith, J. 1978. _The Evolution of Sex_. Cambridge University Press, Cambridge. Google Scholar  * Nei, M. 1972. Genetic distance between populations. _Am Nat_, 106, 283–292. Article

  Google Scholar  * Nei, M. 1973. Analysis of gene diversity in subdivided populations. _Proc Natl Acad Sci USA_, 70, 3321–3323. Article  CAS  Google Scholar  * Olofsson, O. 1918. Studien

uber die Susswasserfauna Spitzbergens. _Zool Bidr Uppsala_, 6, 183–646. Google Scholar  * Ruvinsky, A O, Perelygin, A A, Lobkov, Yu I, and Belyaev, D K. 1986. Factors organising and

maintaining polymorphism in a cyclic parthenogenetic species: _Daphnia pulex_. _Heredity_, 57, 15–22. Article  Google Scholar  * Suomalainen, E. 1962. Significance of parthenogenesis in the

evolution of insects. _Ann Rev Entomol_, 1, 349–366. Article  Google Scholar  * Suomalainen, E. 1969. Evolution in parthenogenetic Curculionidae. _Evol Biol_, 3, 261–296. Google Scholar  *

Suomalainen, E, Saura, A, and Lokki, J. 1987. Polyploidy in association with parthenogenesis. In: Suomalainen, E., Saura, A. and Lokki, J. (eds) _Cytology and Evolution in Parthenogenesis_,

pp. 71–112. CRC Press, Boca Raton, Florida. Google Scholar  * Vandel, A. 1928. La parthénogénèse géographique: contribution a l'étude biologique et cytologique de la parthénogénèse

naturelle. _Bull Biol France et de la Belgique_, 62, 164–281. Google Scholar  * Ward, R D, and Geissler, P A. 1988. Reproductive mode in populations of _Daphnia pulex_ and _Daphnia obtusa_

from the East Midlands of Britain. _Freshw Biol_, 20, 69–73. Article  Google Scholar  * Weider, L J. 1987. Life history variation among low-arctic clones of obligately parthenogenetic

_Daphnia pulex_: a diploid-polyploid complex. _Oecologia_, 73, 251–256. Article  CAS  Google Scholar  * Weider, L J, Beaton, M J, and Hebert, P D N. 1987. Clonal diversity in high-Arctic

populations of _Daphnia pulex_, a polyploid apomictic complex. _Evolution_, 41, 1335–1346. Google Scholar  * Weider, L J, and Hebert, P D N. 1987. Microgeographic genetic heterogeneity of

melanic _Daphnia pulex_ at a low Arctic site. _Heredity_, 58, 391–399. Article  Google Scholar  * Weider, L J, and Hobaek, A. 1994. Molecular biogeography of clonal lineages in a high-arctic

apomictic _Daphnia complex_. _Mol Ecol_. (in press). Article  CAS  Google Scholar  * Williams, G C. 1975. _Sex and Evolution_, Princeton University Press, Princeton. Google Scholar 

Download references AUTHOR INFORMATION Author notes * Melanie A Bickerton Present address: Department of Geography, Loughborough University of Technology, Loughborough, LE11 3TU, U.K.

AUTHORS AND AFFILIATIONS * Department of Human Sciences, Loughborough University of Technology, Loughborough, LE11 3TU, UK Robert D Ward & Melanie A Bickerton * Department of Zoology,

University of Guelph, Guelph, N1G 2W1, Ontario, Canada Terrie Finston & Paul D N Hebert Authors * Robert D Ward View author publications You can also search for this author inPubMed 

Google Scholar * Melanie A Bickerton View author publications You can also search for this author inPubMed Google Scholar * Terrie Finston View author publications You can also search for

this author inPubMed Google Scholar * Paul D N Hebert View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions

ABOUT THIS ARTICLE CITE THIS ARTICLE Ward, R., Bickerton, M., Finston, T. _et al._ Geographical cline in breeding systems and ploidy levels in European populations of _Daphnia pulex_.

_Heredity_ 73, 532–543 (1994). https://doi.org/10.1038/hdy.1994.152 Download citation * Received: 18 March 1994 * Issue Date: 01 November 1994 * DOI: https://doi.org/10.1038/hdy.1994.152

SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to

clipboard Provided by the Springer Nature SharedIt content-sharing initiative KEYWORDS * allozymes * breeding systems * clones * _Daphnia pulex_ * polyploidy * parthenogenesis