Shawn S Jackson

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All areas of physics, astrophysics, mathematics.

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Journals/Publications

• Jackson, S., Simon, A. M., Chen, H., & Jackson, S. S. (0). Cx37 and Cx43 localize to zona pellucida in mouse ovarian follicles. Cell communication & adhesion, 13(1-2).
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  In the ovarian follicle, granulosa cells adjacent to the oocyte extend processes through the zona pellucida matrix, and these projections establish gap junctions both with the oocyte and with neighboring transzonal projections. The identity of connexins contributing to gap junctions between transzonal projections has not been extensively studied. Here, we examined the expression pattern of Cx37 and Cx43 in mouse zona pellucida using multiple connexin-specific antibodies. Immunofluorescence staining revealed abundant Cx37 and Cx43 puncta within the zona pellucida of both preantral and antral follicles. Cx37 persisted in the zona pellucida of mature follicles up to 5 h after an ovulatory stimulus whereas Cx43 was reduced in the zona pellucida by 3 h after an ovulatory stimulus. We suggest that in addition to its role in oocyte-granulosa cell communication, Cx37 could enable a distinct communication pathway between those granulosa cells that are in direct contact with the oocyte.
• Jackson, S., Wedel, A., Kaplan, A., & Jackson, S. S. (2013). High functional load inhibits phonological contrast loss: a corpus study. Cognition, 128(2).
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  For nearly a century, linguists have suggested that diachronic merger is less likely between phonemes with a high functional load--that is, phonemes that distinguish many words in the language in question. However, limitations in data and computational power have made assessing this hypothesis difficult. Here we present the first larger-scale study of the functional load hypothesis, using data from sound changes in a diverse set of languages. Our results support the functional load hypothesis: phoneme pairs undergoing merger distinguish significantly fewer minimal pairs in the lexicon than unmerged phoneme pairs. Furthermore, we show that higher phoneme probability is positively correlated with merger, but that this effect is stronger for phonemes that distinguish no minimal pairs. Finally, within our dataset we find that minimal pair count and phoneme probability better predict merger than change in system entropy at the lexical or phoneme level.
• Jackson, S., Wing, R. A., Ammiraju, J. S., Luo, M., Kim, H., Yu, Y., Kudrna, D., Goicoechea, J. L., Wang, W., Nelson, W., Rao, K., Brar, D., Mackill, D. J., Han, B., Soderlund, C., Stein, L., SanMiguel, P., & Jackson, S. S. (2005). The oryza map alignment project: the golden path to unlocking the genetic potential of wild rice species. Plant molecular biology, 59(1).
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  The wild species of the genus Oryza offer enormous potential to make a significant impact on agricultural productivity of the cultivated rice species Oryza sativa and Oryza glaberrima. To unlock the genetic potential of wild rice we have initiated a project entitled the 'Oryza Map Alignment Project' (OMAP) with the ultimate goal of constructing and aligning BAC/STC based physical maps of 11 wild and one cultivated rice species to the International Rice Genome Sequencing Project's finished reference genome--O. sativa ssp. japonica c. v. Nipponbare. The 11 wild rice species comprise nine different genome types and include six diploid genomes (AA, BB, CC, EE, FF and GG) and four tetrapliod genomes (BBCC, CCDD, HHKK and HHJJ) with broad geographical distribution and ecological adaptation. In this paper we describe our strategy to construct robust physical maps of all 12 rice species with an emphasis on the AA diploid O. nivara--thought to be the progenitor of modern cultivated rice.