Strategies for delivery of CRISPR/Cas-mediated genome editing to obtain edited plants directly without transgene integration.

Increased understanding of plant genetics and the development of powerful and easier-to-use gene editing tools over the past century have revolutionized humankind's ability to deliver precise genotypes in crops. Plant transformation techniques are well developed for making transgenic varieties in certain crops and model organisms, yet reagent delivery and plant regeneration remain key bottlenecks to applying the technology of gene editing to most crops. Typical plant transformation protocols to produce transgenic, genetically modified (GM) varieties rely on transgenes, chemical selection, and tissue culture.

A laboratory and simulation platform to integrate individual life history traits and population dynamics.

Understanding populations is important because they are a fundamental level of biological organization. Individual traits such as aging and lifespan interact in complex ways to determine birth and death and thereby influence population dynamics. However, we lack a deep understanding of the relationships between individual traits and population dynamics.

Reproductive Aging in : From Molecules to Ecology.

Aging animals display a broad range of progressive degenerative changes, and one of the most fascinating is the decline of female reproductive function. In the model organism , hermaphrodites reach a peak of progeny production on day 2 of adulthood and then display a rapid decline; progeny production typically ends by day 8 of adulthood. Since animals typically survive until day 15 of adulthood, there is a substantial post reproductive lifespan.

Lifespan Extension in C. elegans Caused by Bacterial Colonization of the Intestine and Subsequent Activation of an Innate Immune Response.

Mechanisms that control aging are important yet poorly defined. To discover longevity control genes, we performed a forward genetic screen for delayed reproductive aging in C. elegans.

Rapid population-wide declines in stem cell number and activity during reproductive aging in .

hermaphrodites display dramatic age-related decline of reproduction early in life, while somatic functions are still robust. To understand reproductive aging, we analyzed the assembly line of oocyte production that generates fertilized eggs. Aging germlines displayed both sporadic and population-wide changes.

Cell Cycle Analysis in the C. elegans Germline with the Thymidine Analog EdU.

Cell cycle analysis in eukaryotes frequently utilizes chromosome morphology, expression and/or localization of gene products required for various phases of the cell cycle, or the incorporation of nucleoside analogs. During S-phase, DNA polymerases incorporate thymidine analogs such as EdU or BrdU into chromosomal DNA, marking the cells for analysis. For C.

Cell cycle accumulation of the proliferating cell nuclear antigen PCN-1 transitions from continuous in the adult germline to intermittent in the early embryo of C. elegans.

Background: The proliferating cell nuclear antigen (PCNA or PCN-1 in C. elegans), an essential processivity factor for DNA polymerase δ, has been widely used as a marker of S-phase. In C.

Retrotransposons Are the Major Contributors to the Expansion of the Muller F Element.

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (∼5.2 Mb) is the smallest chromosome in , but it is substantially larger (>18.

The Nuclear Receptor HIZR-1 Uses Zinc as a Ligand to Mediate Homeostasis in Response to High Zinc.

Nuclear receptors were originally defined as endocrine sensors in humans, leading to the identification of the nuclear receptor superfamily. Despite intensive efforts, most nuclear receptors have no known ligand, suggesting new ligand classes remain to be discovered. Furthermore, nuclear receptors are encoded in the genomes of primitive organisms that lack endocrine signaling, suggesting the primordial function may have been environmental sensing.

Drosophila muller f elements maintain a distinct set of genomic properties over 40 million years of evolution.

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D.