TY - JOUR
T1 - Ameiotic recombination in asexual lineages of Daphnia
AU - Omilian, Angela R.
AU - Cristescu, Melania E.A.
AU - Dudycha, Jeffry L.
AU - Lynch, Michael
PY - 2006/12/5
Y1 - 2006/12/5
N2 - Despite the enormous theoretical attention given to the evolutionary consequences of sexual reproduction, the validity of the key assumptions on which the theory depends rarely has been evaluated. It is often argued that a reduced ability to purge deleterious mutations condemns asexual lineages to an early extinction. However, most well characterized asexual lineages fail to exhibit the high levels of neutral allelic divergence expected in the absence of recombination. With purely descriptive data, it is difficult to evaluate whether this pattern is a consequence of the rapid demise of asexual lineages, an unusual degree of mutational stability, or recombination. Here, we show in mutation-accumulation lines of asexual Daphnia that the rate of loss of nucleotide heterozygosity by ameiotic recombination is substantially greater than the rate of introduction of new variation by mutation. This suggests that the evolutionary potential of asexual diploid species is not only a matter of mutation accumulation and reduced efficiency of selection, but it underscores the limited utility of using neutral allelic divergence as an indicator of ancient asexuality.
AB - Despite the enormous theoretical attention given to the evolutionary consequences of sexual reproduction, the validity of the key assumptions on which the theory depends rarely has been evaluated. It is often argued that a reduced ability to purge deleterious mutations condemns asexual lineages to an early extinction. However, most well characterized asexual lineages fail to exhibit the high levels of neutral allelic divergence expected in the absence of recombination. With purely descriptive data, it is difficult to evaluate whether this pattern is a consequence of the rapid demise of asexual lineages, an unusual degree of mutational stability, or recombination. Here, we show in mutation-accumulation lines of asexual Daphnia that the rate of loss of nucleotide heterozygosity by ameiotic recombination is substantially greater than the rate of introduction of new variation by mutation. This suggests that the evolutionary potential of asexual diploid species is not only a matter of mutation accumulation and reduced efficiency of selection, but it underscores the limited utility of using neutral allelic divergence as an indicator of ancient asexuality.
KW - Allelic divergence
KW - Loss of heterozygosity
KW - Mutation accumulation
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U2 - 10.1073/pnas.0606435103
DO - 10.1073/pnas.0606435103
M3 - Article
C2 - 17121990
AN - SCOPUS:33845494678
SN - 0027-8424
VL - 103
SP - 18638
EP - 18643
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 49
ER -