The maternal-effect, selfish genetic element Medea is associated with a composite Tc1 transposon

Abstract

Maternal-Effect Dominant Embryonic Arrest (''Medea'') factors are selfish nuclear elements that combine maternal-lethal and zygoticrescue activities to gain a postzygotic survival advantage. We show that Medea 1 activity in Tribolium castaneum is associated with a composite Tc1 transposon inserted just downstream of the neurotransmitter reuptake symporter bloated tubules (blot), whose Drosophila ortholog has both maternal and zygotic functions. The 21.5-kb insertion contains defective copies of elongation initiation factor-3, ATP synthase subunit C, and an RNaseD-related gene, as well as a potentially intact copy of a prokaryotic DUF1703 gene. Sequence comparisons suggest that the current distribution of Medea 1 reflects global emanation after a single transpositional event in recent evolutionary time. The Medea system in Tribolium represents an unusual type of intragenomic conflict and could provide a useful vehicle for driving desirable genes into populations.postzygotic ͉ selfish gene ͉ Tribolium ͉ gene driver

Selfish genetic elements, genetic conflict, and evolutionary innovation

“…A most intriguing example is the maternal effect dominant embryonic arrest (Medea) system in Tribolium beetles (66), which is chromosomally integrated and was discovered in crosses between populations with and without the driver. When females carry the Medea element, their zygotes must also receive the element (either maternally or paternally) or the offspring perish.…”

Coil and shape in Partula suturalis: the rules of form revisited

“…The Partula data set is a rare record of an association in nature between the phenotype and genotype of a maternal-effect locus. Thus, even though Medea loci (Maternal-Effect Dominant Embryonic Arrest) have been the subject of continuing and detailed molecular genetic study (Lorenzen et al, 2008), field surveys have concentrated on their geographic occurrence, while neglecting the details of maternal-offspring transmission (Beeman and Friesen, 1999;Beeman, 2003).…”

Gene Drive Strategies for Population Replacement

“…In Tribolium, Medea dynamics are attributed to an insertion of a composite Tc1 transposon inserted between two genes both having maternal and zygotic components [13]. Remarkably, this system was reverseengineered using entirely synthetic components in laboratory populations of D. melanogaster and was shown to rapidly drive population replacement [14,64].…”

“…Two of the most promising gene drive systems at present also involve technologies inspired by Nature-the use of homing endonuclease genes (HEGs) observed to spread in fungi, plants, and bacteria [11], and a selfish genetic element known as Medea observed to spread in Tribolium beetles [12,13]. A synthetic Medea element has been developed in Drosophila that works by the hypothesis that Medea encodes both a maternally expressed toxin and a zygotically expressed antidote [14].…”