The genetic outcomes of sex and recombination in long-term functionally parthenogenetic lineages of Australian Sitobion aphids

Alexandra Wilson, Paul Sunnuck

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The typical life cycle of an aphid is cyclical parthenogenesis which involves the alternation of sexual and asexual reproduction. However, aphid life cycles, even within a species, can encompass everything on a continuum from obligate sexuality, through facultative sexuality to obligate asexuality. Loss of the sexual cycle in aphids is frequently associated with the introduction of a new pest and can occur for a number of environmental and genetic reasons. Here we investigate loss of sexual function in Sitobion aphids in Australia. Specifically, we aimed to determine whether an absence of sexual reproduction in Australian Sitobion results from genetic loss of sexual function or environmental constraints in the introduced range. We addressed our aims by performing a series of breeding experiments. We found that some lineages have genetically lost sexual function while others retain sexual function and appear environmentally constrained to asexuality. Further, in our crosses, using autosomal and X-linked microsatellite markers, we identified processes deviating from normal Mendelian segregation. We observed strong deviations in X chromosome transmission through the sexual cycle. Additionally, when progeny genotypes were examined across multiple loci simultaneously we found that some multilocus genotypes are significantly over-represented in the sample and that levels of heterozygosity were much higher than expected at almost all loci. This study demonstrates that strong biases in the transmission of X chromosomes through the sexual cycle are likely to be widespread in aphids. The mechanisms underlying these patterns are not clear. We discuss several possible alternatives, including mutation accumulation during periods of functional asexuality and genetic imprinting.

Original languageEnglish
Pages (from-to)175-185
Number of pages11
JournalGenetical Research
Volume87
Issue number3
DOIs
StatePublished - Jun 1 2006
Externally publishedYes

Fingerprint

Aphids
Genetic Recombination
Sexuality
X Chromosome
Life Cycle Stages
Genotype
Asexual Reproduction
Parthenogenesis
Genomic Imprinting
Microsatellite Repeats
Breeding
Reproduction

ASJC Scopus subject areas

  • Genetics

Cite this

The genetic outcomes of sex and recombination in long-term functionally parthenogenetic lineages of Australian Sitobion aphids. / Wilson, Alexandra; Sunnuck, Paul.

In: Genetical Research, Vol. 87, No. 3, 01.06.2006, p. 175-185.

Research output: Contribution to journalArticle

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