Moira Jane Sheehan

Dr. Moira Jane Sheehan

Cornell Institute of Biotechnology, Cornell University, Ithaca, New York, USA
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Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 December 2006 in The Plant Journal
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Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
LKLisa M. Kennedy
Lisa M. Kennedy
DCDenise E. Costich
Denise E. Costich
TBThomas Brutnell
Thomas Brutnell
Summary: Phytochromes are the primary red/far‐red photoreceptors of higher plants, mediating numerous developmental processes throughout the life cycle, from germination to flowering. In seed plants, phytochromes are encoded by a small gene family with each member performing both distinct and redundant roles in mediating physiological responses to light cues. Studies in both eudicot and monocot species have defined a central role for phytochrome B in mediating responses to light in the control of several agronomically important traits, including plant height, transitions to flowering and axillary branch meristem development. Here we characterize Mutator‐induced alleles of PhyB1 and a naturally occurring deletion allele of PhyB2 in Zea mays (maize). Using single and double mutants, we show that the highly similar PhyB1 and PhyB2 genes encode proteins with both overlapping and non‐redundant functions that control seedling and mature plant traits. PHYB1 and PHYB2 regulate elongation of sheath and stem tissues of mature plants and contribute to the light‐mediated regulation of PhyA and Cab gene transcripts. However, PHYB1 and not PHYB2 contributes significantly to the inhibition of mesocotyl elongation under red light, whereas PHYB2 and to a lesser extent PHYB1 mediate the photoperiod‐dependent floral transition. This sub functionalization of PHYB activities in maize has probably occurred since the tetraploidization of maize, and may contribute to flowering time variation in modern‐day varieties.

8 December 2009 in Proceedings of the National Academy of Sciences
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Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
WPWojciech P. Pawlowski
Wojciech P. Pawlowski
The ability of chromosomes to move across the nuclear space is essential for the reorganization of the nucleus that takes place in early meiotic prophase. Chromosome dynamics of prophase I have been studied in budding and fission yeasts, but little is known about this process in higher eukaryotes, where genomes and chromosomes are much larger and meiosis takes a longer time to complete. This knowledge gap has been mainly caused by difficulties in culturing isolated live meiocytes of multicellular eukaryotes. To study the nuclear dynamics during meiotic prophase in maize, we established a system to observe live meiocytes inside intact anthers. We found that maize chromosomes exhibited extremely dynamic and complex motility in zygonema and pachynema. The movement patterns differed dramatically between the two stages. Chromosome movements included rotations of the entire chromatin and movements of individual chromosome segments, which were mostly telomere-led. Chromosome motility was coincident with dynamic deformations of the nuclear envelope. Both, chromosome and nuclear envelope motility depended on actin microfilaments as well as tubulin. The complexity of the nuclear movements implies that several different mechanisms affect chromosome motility in early meiotic prophase in maize. We propose that the vigorous nuclear motility provides a mechanism for homologous loci to find each other during zygonema.

1 November 2010 in The Plant Genome
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DCDenise E. Costich
Denise E. Costich
BFBernd Friebe
Bernd Friebe
Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
MCMichael D. Casler
Michael D. Casler
EBEdward S. Buckler
Edward S. Buckler
Switchgrass (Panicum virgatum L.), a native perennial dominant of the prairies of North America, has been targeted as a model herbaceous species for biofeedstock development. A flow-cytometric survey of a core set of 11 primarily upland polyploid switchgrass accessions indicated that there was considerable variation in genome size within each accession, particularly at the octoploid (2n = 8X = 72 chromosome) ploidy level. Highly variable chromosome counts in mitotic cell preparations indicated that aneuploidy was more common in octoploids (86.3%) than tetraploids (23.2%). Furthermore, the incidence of hyper- versus hypoaneuploidy is equivalent in tetraploids. This is clearly not the case in octoploids, where close to 90% of the aneuploid counts are lower than the euploid number. Cytogenetic investigation using fluorescent in situ hybridization (FISH) revealed an unexpected degree of variation in chromosome structure underlying the apparent genomic instability of this species. These results indicate that rapid advances in the breeding of polyploid biofuel feedstocks, based on the molecular-genetic dissection of biomass characteristics and yield, will be predicated on the continual improvement of our understanding of the cytogenetics of these species. Copyright © 2010. . Copyright © 2010 Crop Science Society of America

1 March 2005 in Trends in Plant Science
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RSRuairidh J.H. Sawers
Ruairidh J.H. Sawers
Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
TBThomas Brutnell
Thomas Brutnell

11 July 2023 in Genetic Resources
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DZDongyan Zhao
Dongyan Zhao
KMKatherine Maria Mejia-Guerra
Katherine Maria Mejia-Guerra
MMMarcelo Mollinari
Marcelo Mollinari
DDeborah Samac
Deborah Samac
BIBrian Irish
Brian Irish
Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
Small public breeding programmes have many barriers to adopting technology, particularly creating and using genetic marker panels for genomic-based decisions in selection. Here we report the creation of a DArTag panel of 3,000 loci distributed across the alfalfa (Medicago sativa L.) genome for use in molecular breeding and genomic insight. The creation of this marker panel brings cost-effective and rapid genotyping capabilities to alfalfa breeding programmes. The open access provided by this platform will allow genetic data sets generated on the marker panel to be compared and joined across projects, institutions and countries. This genotyping resource has the power to make routine genotyping a reality for any breeder of alfalfa.

1 September 2000 in Plant Science
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JWJianmin Wang
Jianmin Wang
Moira Jane SheehanMoira Jane Sheehan
Moira Jane Sheehan
HBHeather Brookman
Heather Brookman
MTMichael P Timko
Michael P Timko