The Flow Cytometry Core of the National Human Genome Research Institute has the goal of providing all NHGRI investigators with access to high quality flow cytometry services. The Core serves to enhance the scope and quality of scientific research performed by the Institute. Instrumentation: The Core is equipped with two Becton Dickinson FACSARIAs which now can identify up to 13 fluorescent parameters and sort into tubes, 96 or 386 well plates, or slides; one Becton Dickinson LSRII which is used for direct flow cytometry analysis applications (13 color), including high throughput analysis; and one four color BD FACSCalibur. The Flow Core maintains a laser scanning cytometer (LCS). Current applications (100%) are focused on zebra fish projects including drug screens and blood development. An autoMACS Pro Separator was added in 2015. This bench top instrument is used for high-speed magnetic cell isolation of multiple samples. The autoMACS Pro Separator is designed for cell isolation in a fully automated, walk-away fashion. Services provided by the Core include planning, design, execution, and analysis of experiments involving flow cytometry. These experiments range from simple fluorescent protein quantitation to complex 13-color analysis and isolation of cells both from cell lines and any single cell tissue sample including, but not limited to blood, bone marrow, lymph node, spleen, thymus, lung, and neuronal cells. The Core has been involved in various applications over the past year including the isolation of tissue cell populations for animal transplantation experiments; isolation of blood cell sub-populations for analysis of functional cellular properties and gene transcription profiles, as well as high throughput screening of enhancer regions. Attached is a chart showing Flow Core use from 2012-2015 The Flow Core added the Miltenyi biotech autoMACS Pro Separator in 2015 for the magnetic isolation of cell populations from multiple samples. We have upgraded both sorters to have 13-color capability and will introduce index sorting before the end of the fiscal year. The index-sorting feature enables the investigator to sort cells into single wells of plates, and also easily identify them on plots, in statistics views, and in a detailed results file. Concerns include the limited access to the LSRII. This instrument is currently at maximum capacity and is used seven days/week including evenings. We would like to add a 561nm laser to this instrument. The incorporation of the 561-nm laser into the BD LSRII will provide the capability to physically separate the excitation and emission of two commonly used fluorochromes, FITC and PE, resulting in the elimination of spillover between the emission spectra of these fluorochromes. In addition, the 561-nm laser efficiently excites fruit fluorescent proteins such as mCherry.