Genetic loci with parent‐of‐origin effects cause hybrid seed lethality in crosses between
            Mimulus
            species

SummaryRationaleHybrid seed inviability (HSI) is a common reproductive barrier in angiosperms, yet the evolutionary and developmental drivers of HSI remain largely unknown. We test whether conflict between maternal and paternal interests in resource allocation to developing offspring (i.e. parental conflict) are associated with HSI and determine the degree of developmental parallelism between independent incidences of HSI in Mimulus.MethodsWe quantified HSI between M. guttatus and two clades of M. decorus with oppositely asymmetric incompatibilities and surveyed development of hybrid and parental seeds.Key ResultsCrosses between M. guttatus and both clades of M. decorus show parent-of-origin effects on reciprocal F1 seed development, but in opposing directions. Inviable hybrid seeds exhibit paternal excess phenotypes, wherein endosperm is large and chaotic while viable hybrid seeds produce endosperm cells that are smaller and less prolific (i.e. maternal-excess phenotypes).Main ConclusionsWe find strong parent-of-origin effects on development in reciprocal F1s in multiple incidences of HSI in Mimulus. These patterns suggest that parental conflict may be an important force generating HSI in this group, and mismatches between maternal and paternal contributions to developing seeds result in repeatable developmental defects in hybrids.

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Genetic loci with parent of origin effects cause hybrid seed lethality between Mimulus species

10.1101/022863 ◽

2015 ◽

Author(s):

Austin G Garner ◽

Amanda M Kenney ◽

Lila Fishman ◽

Andrea L Sweigart

Keyword(s):

Genetic Mapping ◽

Diploid Species ◽

Good Evidence ◽

Flowering Plants ◽

Hybrid Seed ◽

Transmission Ratio Distortion ◽

F1 Hybrid ◽

Primary Driver ◽

Parent Of Origin ◽

Origin Effects

The classic finding in both flowering plants and mammals that hybrid lethality often depends on parent of origin effects suggests that divergence in the underlying loci might be an important source of hybrid incompatibilities between species. In flowering plants, there is now good evidence from diverse taxa that seed lethality arising from interploidy crosses is often caused by endosperm defects associated with deregulated imprinted genes. A similar seed lethality phenotype occurs in many crosses between closely related diploid species, but the genetic basis of this form of early-acting F1 postzygotic reproductive isolation is largely unknown. Here, we show that F1 hybrid seed lethality is an exceptionally strong isolating barrier between two closely related Mimulus species, M. guttatus and M. tilingii, with reciprocal crosses producing less than 1% viable seeds. Using a powerful crossing design and high-resolution genetic mapping, we identify both maternally- and paternally-derived loci that contribute to hybrid seed incompatibility. Strikingly, these two sets of loci are largely non-overlapping, providing strong evidence that genes with parent of origin effects are the primary driver of F1 hybrid seed lethality between M. guttatus and M. tilingii. We find a highly polygenic basis for both parental components of hybrid seed lethality suggesting that multiple incompatibility loci have accumulated to cause strong postzygotic isolation between these closely related species. Our genetic mapping experiment also reveals hybrid transmission ratio distortion and chromosomal differentiation, two additional correlates of functional and genomic divergence between species.

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Analysis of parent of origin effects in Sorbs using long range phasing algorithms

Diabetologie und Stoffwechsel ◽

10.1055/s-0034-1375033 ◽

2014 ◽

Vol 9 (S 01) ◽

Author(s):

X Liu ◽

M Scholz ◽

A Tönjes ◽

M Stumvoll ◽

PF Stadler ◽

...

Keyword(s):

Long Range ◽

Parent Of Origin ◽

Origin Effects

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Parent-of-origin effects on voluntary exercise levels and body composition in mice

Physiological Genomics ◽

10.1152/physiolgenomics.00139.2009 ◽

2010 ◽

Vol 40 (2) ◽

pp. 111-120 ◽

Cited By ~ 17

Author(s):

Scott A. Kelly ◽

Derrick L. Nehrenberg ◽

Kunjie Hua ◽

Ryan R. Gordon ◽

Theodore Garland ◽

...

Keyword(s):

Body Composition ◽

Body Fat ◽

Wheel Running ◽

Voluntary Exercise ◽

Phenotypic Variance ◽

In Utero Environment ◽

Dependent Activity ◽

Health Related ◽

Parent Of Origin ◽

Origin Effects

Despite the health-related benefits of exercise, many people do not engage in enough activity to realize the rewards, and little is known regarding the genetic or environmental components that account for this individual variation. We created and phenotyped a large G4 advanced intercross line originating from reciprocal crosses between mice with genetic propensity for increased voluntary exercise (HR line) and the inbred strain C57BL/6J. G4 females (compared to males) ran significantly more when provided access to a running wheel and were smaller with a greater percentage of body fat pre- and postwheel access. Change in body composition resulting from a 6-day exposure to wheels varied between the sexes with females generally regulating energy balance more precisely in the presence of exercise. We observed parent-of-origin effects on most voluntary wheel running and body composition traits, which accounted for 3–13% of the total phenotypic variance pooled across sexes. G4 individuals descended from progenitor (F0) crosses of HR♀ and C57BL/6J♂ ran greater distances, spent more time running, ran at higher maximum speeds/day, and had lower percent body fat and higher percent lean mass than mice descended from reciprocal progenitor crosses (C57BL/6J♀ × HR♂). For some traits, significant interactions between parent of origin and sex were observed. We discuss these results in the context of sex dependent activity and weight loss patterns, the contribution of parent-of-origin effects to predisposition for voluntary exercise, and the genetic (i.e., X-linked or mtDNA variations), epigenetic (i.e., genomic imprinting), and environmental (i.e., in utero environment or maternal care) phenomena potentially modulating these effects.

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