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Titolo:
Clonal organisms and the benefits of sex
Autore:
Vrijenhoek, RC;
Indirizzi:
Rutgers State Univ, Ctr Theoret & Appl Genet, New Brunswick, NJ 08901 USA Rutgers State Univ New Brunswick NJ USA 08901 New Brunswick, NJ 08901 USA
Titolo Testata:
ADVANCES IN MOLECULAR ECOLOGY
, volume: 306, anno: 1998,
pagine: 151 - 172
SICI:
0258-1213(1998)306:<151:COATBO>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOXINUS-EOS-NEOGAEUS; HYBRIDOGENETIC RANA-ESCULENTA; NICHE-VARIATION MODEL; BRINE SHRIMP ARTEMIA; MITOCHONDRIAL-DNA; UNISEXUAL FISH; MULLER RATCHET; GEOGRAPHIC PARTHENOGENESIS; ALBURNOIDES COMPLEX; GENETIC DISSECTION;
Tipo documento:
Review
Natura:
Collana
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
149
Recensione:
Indirizzi per estratti:
Indirizzo: Vrijenhoek, RC Rutgers State Univ, Ctr Theoret & Appl Genet, New Brunswick, NJ 08901 USA Rutgers State Univ New Brunswick NJ USA 08901 NJ 08901 USA
Citazione:
R.C. Vrijenhoek, "Clonal organisms and the benefits of sex", NATO AD S A, 306, 1998, pp. 151-172

Abstract

Obligately asexual species are very uncommon among multicellular plants and metazoan animals; yet studies of these rare exceptions to the "rule of sex" provide insights into the long- and short-term benefits of sexual reproduction. Lessons to be learned from clones are especially relevant as we enter an era when the artificial cloning of mammals (and potentially humans) is no longer a fantasy. Sexual reproduction is the ancestral condition for multicellular eukaryotes. Some sexual species have genes that control the switch to asexual reproduction, bur many asexual lineages arise because of cytogenetic accidents (e.g. interspecific hybridization and polyploidization)that disrupt meiosis. Molecular studies reveal that many asexual taxa are composed of multiple clones that arose independently from the sexual progenitors. Are the successful clones ecological generalists or specialists? Some appear to have a wide tolerance of environmental conditions, and many others appear to flourish under a narrower range of conditions. The niche characteristics of clones are a product of the competitive milieu in which asexual lineages arise. Broadly tolerant clones may be favoured in marginal habitats, where they escape from competition with their sexual ancestors. Conversely, specialized clones may be favoured if the asexual population must live and compete with closely related sexual ancestors (e.g, sperm-dependentparthenogens). Despite their ecological success, asexual lineages appear to be evolutionary dead ends. Mutational meltdown hastens the demise of individual clones, but some asexual taxa may persist through periodic additionsor replacements of nuclear genomes and genes from extant sexual relatives. With few exceptions, molecular studies provide little evidence for ancientclonal lineages or diversified asexual taxa.

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Documento generato il 06/07/20 alle ore 07:14:54