Allelic expression of IGF2 in live-bearing, matrotrophic fishes

Lawton, Betty R.; Sevigny, Leila M.; Obergfell, Craig; Reznick, David N.; O’Neill, Rachel J.; O’Neill, Michael

doi:10.1007/s00427-004-0463-8

Cited by 41 publications

(36 citation statements)

References 17 publications

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“…Our knowledge of imprinting in viviparous animals other than mammals is limited. However, Lawton et al (2005) recently found that the gene Igf2, which is imprinted in mammals, is biallelically expressed in two matrotrophic poeciliids (Poeciliopsis prolifica and Heterandria formosa). Thus, no evidence of an important role of imprinting in poeciliids has been found.…”

Section: Discussionmentioning

confidence: 99%

Testing the Viviparity‐Driven‐Conflict Hypothesis: Parent‐Offspring Conflict and the Evolution of Reproductive Isolation in a Poeciliid Fish

Schrader

Travis

2008

The American Naturalist

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The evolution of viviparity increases the potential for genomic conflicts between mothers and offspring over the level of maternal investment. The viviparity-driven-conflict hypothesis predicts that such conflicts will drive the evolution of asymmetrical reproductive isolation between populations with divergent mating systems. We tested this hypothesis using crosses between populations of a poeciliid fish that differ in their level of polyandry. Our results support the prediction of an asymmetry in the rate of spontaneous abortion in reciprocal crosses, with the highest rate occurring in crosses between females from a relatively monandrous population and males from a relatively polyandrous population. The patterns of offspring size were not consistent with the pattern predicted by the viviparity-driven-conflict hypothesis: crosses between a monandrous female and a polyandrous male did not produce larger offspring than the reciprocal cross. This discrepancy was due to the presence of an effect of the maternal population on offspring size: polyandrous females produced larger offspring than monandrous females. In addition, offspring size was positively correlated with maternal size in crosses involving a polyandrous male. We discuss these results in light of models for intra- and intergenomic epistasis and the rapid origin of asymmetric reproductive isolation in viviparous taxa.

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Section: Discussionmentioning

confidence: 99%

Testing the Viviparity‐Driven‐Conflict Hypothesis: Parent‐Offspring Conflict and the Evolution of Reproductive Isolation in a Poeciliid Fish

Schrader

Travis

2008

The American Naturalist

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“…Located downstream of IGF2 is the untranslated RNA H19 , which is expressed solely from the maternally derived chromosome [24],[25]. Biallelic expression of IGF2 was discovered in the egg-laying monotreme mammals [26], birds [22],[27] and fish [28], implying that imprinting of this region evolved at the same time as viviparity, 180-210MYA [29].…”

Section: Introductionmentioning

confidence: 99%

The Evolution of Epigenetic Regulators CTCF and BORIS/CTCFL in Amniotes

2008

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CTCF is an essential, ubiquitously expressed DNA-binding protein responsible for insulator function, nuclear architecture, and transcriptional control within vertebrates. The gene CTCF was proposed to have duplicated in early mammals, giving rise to a paralogue called “brother of regulator of imprinted sites” (BORIS or CTCFL) with DNA binding capabilities similar to CTCF, but testis-specific expression in humans and mice. CTCF and BORIS have opposite regulatory effects on human cancer-testis genes, the anti-apoptotic BAG1 gene, the insulin-like growth factor 2/H19 imprint control region (IGF2/H19 ICR), and show mutually exclusive expression in humans and mice, suggesting that they are antagonistic epigenetic regulators. We discovered orthologues of BORIS in at least two reptilian species and found traces of its sequence in the chicken genome, implying that the duplication giving rise to BORIS occurred much earlier than previously thought. We analysed the expression of CTCF and BORIS in a range of amniotes by conventional and quantitative PCR. BORIS, as well as CTCF, was found widely expressed in monotremes (platypus) and reptiles (bearded dragon), suggesting redundancy or cooperation between these genes in a common amniote ancestor. However, we discovered that BORIS expression was gonad-specific in marsupials (tammar wallaby) and eutherians (cattle), implying that a functional change occurred in BORIS during the early evolution of therian mammals. Since therians show imprinting of IGF2 but other vertebrate taxa do not, we speculate that CTCF and BORIS evolved specialised functions along with the evolution of imprinting at this and other loci, coinciding with the restriction of BORIS expression to the germline and potential antagonism with CTCF.

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“…The phylogenetic distribution of known cases of vertebrate imprinting suggests that imprinting evolved in the mammalian line at about the same time as the placenta, when therians diverged from monotremes. The absence of Igf2 imprinting in two poeciliid fish (Lawton et al 2005) that have independently evolved placentas (Reznick et al 2002), however, means that the origin of the mammalian placenta was not a sufficient condition for the origin of imprinting.…”

Section: Introductionmentioning

confidence: 99%

Effects of genomic imprinting on quantitative traits

Spencer

2008

Genetica

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Standard Mendelian genetic processes incorporate several symmetries, one of which is that the level of expression of a gene inherited from an organism's mother is identical to the level should that gene have been inherited paternally. For a small number of loci in a variety of taxa, this symmetry does not hold; such genes are said to be "genomically imprinted" (or simply "imprinted"). The best known examples of imprinted loci come from mammals and angiosperms, although there are also cases from several insects and some data suggesting that imprinting exists in zebra fish. Imprinting means that reciprocal heterozygotes need not be, on average, phenotypically identical. When this difference is incorporated into the standard quantitative-genetic model for two alleles at a single locus, a number of standard expressions are altered in fundamental ways. Most importantly, in contrast to the case with euMendelian expression, the additive and dominance deviations are correlated. It would clearly be of interest to be able to separate imprinting effects from maternal genetic effects, but when the latter are added to the model, the well-known generalized least-squares approach to deriving breeding values cannot be applied. Distinguishing these two types of parent-of-origin effects is not a simple problem and requires further research.

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Allelic expression of IGF2 in live-bearing, matrotrophic fishes

Cited by 41 publications

References 17 publications

Testing the Viviparity‐Driven‐Conflict Hypothesis: Parent‐Offspring Conflict and the Evolution of Reproductive Isolation in a Poeciliid Fish

Testing the Viviparity‐Driven‐Conflict Hypothesis: Parent‐Offspring Conflict and the Evolution of Reproductive Isolation in a Poeciliid Fish

The Evolution of Epigenetic Regulators CTCF and BORIS/CTCFL in Amniotes

Effects of genomic imprinting on quantitative traits

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