Endomeiosis in parthenogenetic lines of Aphids

Cognetti, Giuseppe

doi:10.1007/bf02160362

Cited by 54 publications

(11 citation statements)

References 6 publications

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“…Conversion, which is one way of recombination, has been considered as improbable in apomictic animals, however, somatic crossing-over (endomeiosis) were offered to account for sudden bursts of variation in parthenogenetic aphids and cladoceran populations (BACCI et al 1961;COGNETTI 1961). According to COGNETTI (1961) pairing of chromosomes leads to chiasma formation and gene recombination. These conclusions were nevertheless not concord with studies of SUO-MALAINEN (1950) and BLACKMAN (1978) which were against possibility of endomeiotic recombination events.…”

Section: Discussionmentioning

confidence: 99%

Genetic Constitution of Parthenogenetic Form of Polydrusus inustus (Coleoptera: Curculionidae) – Hints of Hybrid Origin and Recombinations

Kajtoch¹,

Lachowska‐Cierlik²

2009

folia biol (krakow)

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Genetic constitution of parthenogenetic form of Polydrusus inustus (Coleoptera: Curculionidae) hints of hybrid origin and recombinations. Folia biol. (Kraków) #%: 149-156. Asexual reproduction among insects may arise spontaneously, as a result of infectious agents or hybridization between phylogenetically distinct organisms. Polyploidy, which may be the result of auto-or allopoliploidization (also associated with hybridization), is often connected with parthenogenesis. However, all studied parthenogens of weevils were apomictic, rare meiotic stages have been observed in a few of them what could suggests in their genomes besides the mutational changeability also recombination may occurs. We studied the level of heterozygosity in Internal Transcribed Spacer 2 sequences, and congruence of mitochondrial (cytochrome B) and nuclear genealogies among individuals of parthenogenetic form of Polydrusus inustus. High frequency (87.0%) of heterozygotes in ITS2 sequences may indicate a hybrid origin of the parthenogen. It is possible that this parthenogenetic form arose via a hybridization event between phylogenetically distinct lineages of bisexual P. inustus, known only from Georgia and Turkey, or between this species and one of the closely relatives from the subgenus Scythodrusus. Although result of partition-homogeneity test did not show significant incongruence of mitochondrial and nuclear genealogies, in the network was detected one loop. Most probable explanations for existence of that loop in parthenogenetic form and for origin of rare homozygotes, which were detected in ITS2 sequences, is gene conversion. It is supported by recently cytogenetic studies indicating rare meiotic stages during the oogenesis of triploids of P. inustus.

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Section: Discussionmentioning

confidence: 99%

Genetic Constitution of Parthenogenetic Form of Polydrusus inustus (Coleoptera: Curculionidae) – Hints of Hybrid Origin and Recombinations

Kajtoch¹,

Lachowska‐Cierlik²

2009

folia biol (krakow)

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“…The occurrence of both oocytes and embryos in some aphids under transitional photoperiods is probably another consequence of an intermediate JH titre. This may fluctuate; above a certain threshold concentration it may cause the aphid's oogonia to divide (a-or endomeiotically; Cognetti, 1961) into diploid embryos; below this level the oogonia may be able to undergo complete meiosis and become haploid eggs. A differential sensitivity of the oogonia in the germaria of different ovarioles is probably also involved.…”

Section: Discussionmentioning

confidence: 99%

INFLUENCE OF DAYLENGTH ON THE PRODUCTION OF PARTHENOGENETIC AND SEXUAL FEMALES OF APHIS FABAE AT 17.5°

Tsitsipis

Mittler

1977

Entomologia Exp Applicata

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When apterous virginoparae of Aphis fabae and their progenies were raised at 17.5° on leaf discs of Vicia faba under photoperiods of 12 h or less per day, more alatae occurred among the progenies than under longer photoperiods. The alatae developed exclusively into gynoparae at 4, 10 and 12 h light per day and almost all did so at 2 h. At 13 h 45 min, 14 h, 16 h, and 24 h all the alatae developed into virginoparae. At transitional photoperiods ranging from 13 h 6 min to 13 h 28 min, both alate morphs occurred. They could both be deposited by a single apterous virginopara and produce intermorphs containing eggs and embryos. Under most light regimes, a proportion of the gynoparae (generally < 10%) produced some apterous virginoparae, gynoparae, and males after producing a number of oviparae. Alate virginoparae produced almost three times as many larvae as did the gynoparae. By transferring alatiform larvae produced by apterae raised at short day (SD: 10 h light) to long day (LD: 16 h light) or vice versa, a strong prenatal influence of SD on gynopara production was demonstrated. SD also had a postnatal influence on presumptive virginoparous alatiforms, if they were transferred to SD already in the 1st instar. Alatiform larvae could be influenced by SD or LD as late as in the 3d instar if they and their mothers had been maintained under a weak short (13 h 6 min) or a weak long day (13 h 45 min). The results are discussed in relation to possible hormonal mechanisms of morph determination. ZUSAMMENFASSUNG EINFLUSS DER TAGESLÄNGE AUF DIE ERZEUGUNG VON PARTHENOGENETISCHEN UND SEXUELLEN WEIBCHEN VON APHIS FABAE BEI 17.5° Wenn ungeflügelte, virginopare Aphis fabae und ihre Nachkommen gehalten wurden bei 17,5° auf Blattscheiben von Vicia faba bei Fotoperioden von 12 oder weniger Stunden je Tag, so entstanden mehr Geflügelte unter den Nachkommen als unter längeren Fotoperioden. Die Geflügelten entwickelten sich ausschliesslich zu Gynoparen bei 4, 10 und 12 h Licht je Tag und fast alle bei 2 h. Bei 13 h 45 min, 14, 16 und 24 h entwickelten sich alle Geflügelten zu Virginoparen. Bei Übergangsfotoperioden zwischen 13 h 6 min und 13 h 28 min kamen beide geflügelte Morphen vor. Diese konnten beide von einer einzigen ungeflügelten Virginopara abgesetzt werden und Zwischenformen mit Eiern und Embryonen erzeugen. Bei den meisten Fotoperioden erzeugte ein Teil der Gynoparen (meist < 10%) einige ungeflügelte Virginopare, Gynopare und Männchen, nachdem sie eine Anzahl von Oviparen erzeugt hatten. Geflügelte Virginopare erzeugten fast dreimal so viele Larven als wie Gynopare es tun. Wenn man alatiforme Larven, deren ungeflügelte Mütter bei Kurztag (KT: 10 h Licht) gehalten waren, in Langtag (LT: 16 h Licht) übertrug oder umgekehrt, so zeigte sich ein starker pränataler Einfluss des KT auf die Gynoparenerzeugung. KT hatte auch einen postnatalen Einfluss auf präsumptive virginopare geflügelte Formen, wenn diese schon im I. Larvenstadium übertragen wurden. Alatiforme Larven konnten selbst noch im 3. Stadium durch KT oder LT beeinflusst we...

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“…) are commonly referred to as clones. Despite claims of`endomeiosis' (Cognetti, 1961), there is good molecular genetic evidence for the apomictic form of reproduction in aphids. No variation in rDNA Shufran et al, 1991), minisatellite DNA (Carvalho et al, 1991;De Barro et al, 1994), arbitrarily primed (AP-PCR) DNA ®ngerprints (Fukatsu & Ishikawa, 1994), or allozymes (Suomalainen et al, 1980) has been detected within aphid clones.…”

Section: Introductionmentioning

confidence: 99%

Generation of clonal diversity by sexual reproduction in the greenbug, Schizaphis graminum

Shufran

Peters

Webster

1997

Insect Molecular Biology

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In the United States, the greenbug, Schizaphis graminum (Rondani), reproduces primarily by apomictic parthenogenesis. Although a periodic sexual cycle exists, the extent to which it occurs naturally and its influence on the genetic variability of greenbug populations is unclear. Length variation in the intergenic spacer (IGS) of the rRNA cistron in the greenbug indicates that populations are made up of many genetically distinct clones. Previous laboratory studies have shown the stability of the IGS within parthenogenetic clones. By inducing the sexual reproductive cycle of the greenbug, we conducted both Intra- and inter-clone matings and studied the inheritance of the IGS in the offspring. In both mating schemes, rearrangements in the IGS were apparent. IGS diversity found among the offspring could be attributed to unequal cross-over and probably other molecular drive events during meiosis. Periodic sexual reproduction is a primary mechanism for the generation and maintenance of genetic variability in greenbug populations, and explains the level of clonal diversity found in previous studies.

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Endomeiosis in parthenogenetic lines of Aphids

Cited by 54 publications

References 6 publications

Genetic Constitution of Parthenogenetic Form of Polydrusus inustus (Coleoptera: Curculionidae) – Hints of Hybrid Origin and Recombinations

Genetic Constitution of Parthenogenetic Form of Polydrusus inustus (Coleoptera: Curculionidae) – Hints of Hybrid Origin and Recombinations

INFLUENCE OF DAYLENGTH ON THE PRODUCTION OF PARTHENOGENETIC AND SEXUAL FEMALES OF APHIS FABAE AT 17.5°

Generation of clonal diversity by sexual reproduction in the greenbug, Schizaphis graminum

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