THE GOAL OF THIS WORK IS TO UNDERSTAND THE BIOLOGY OF CELLS WITHIN THE MAMMARY GLANDS/UDDER, WHERE EACH CELL PRODUCES A SMALL AMOUNT OF MILK THAT CONTRIBUTES TO A LARGE DAILY OUTPUT THAT IS IMPORTANT FOR BOTH DAIRY FOOD PRODUCTS, AND FOR REARING OFFSPRING DESTINED FOR ANIMAL GROWTH AND FUTURE FOOD PRODUCTION. THE SPECIFIC FOCUS OF THIS RESEARCH IS A NEWLY-IDENTIFIED POPULATION OF CELLS HAVING 2 NUCLEI, WHERE TRADITIONALLY, CELLS IN THE MAMMARY GLAND WERE CONSIDERED TO HAVE ONLY A SINGLE NUCLEUS. THESE "BINUCLEATED" CELLS WERE RECENTLY DESCRIBED IN THE MAMMARY GLANDS OF MICE, YET THEIR FUNCTION IS UNCLEAR IN OTHER SPECIES INCLUDING IN A RANGE OF LIVESTOCK SPECIES. OUR GOAL IS TO UNDERSTAND THE DISTRIBUTION OF THESE CELLS, THE WAY(S) THEY CONTRIBUTE TO MILK PRODUCTION, AND WHETHER THEY HAVE DIFFERENT GENETIC POTENTIAL COMPARED TO THOSE CELLS HAVING JUST A SINGLE NUCLEUS. THE WAYS IN WHICH WE WILL PURSUE THESE QUESTIONS IS MULTI-PRONGED. FIRST, WE WILL SEEK TO MEASURE THE FREQUENCY OF THESE CELLS AT DIFFERENT STAGES OF THE LACTATION CYCLE IN BOTH COWS AND SOWS, USING HIGH-RESOLUTION MICROSCOPY AND METHODS THAT WILL ALLOW US TO EXAMINE ALL THE INDIVIDUAL CELLS AND THEIR LOCATION WITHIN THE GLAND. WE WILL ALSO ASSESS WHETHER DIFFERENT INTERVENTIONS THAT ARE KNOWN TO CHANGE MILK PRODUCTION POTENTIAL LEAD TO AN ALTERATION IN THE ABUNDANCE OF THESE CELLS IN THE MAMMARY GLANDS. FROM HERE WE WILL TEST WHETHER WE CAN "SHIFT" THE ABUNDANCE OF THESE CELLS IN THE UDDER, AND USE THIS APPROACH TO DETERMINE WHETHER THIS LEADS TO AN ALTERED MILK PRODUCTION OUTPUT AS WE TRACK THESE CELLS AND THEIR APPEARANCE/DISAPPEARANCE. THIS APPROACH WILL BE ACCOMPLISHED BOTH IN ANIMALS INDUCED TO PRODUCE MILK OUTSIDE OF A PREGNANCY, AS WELL AS IN A CULTURE SYSTEM THAT WILL ALLOW US TO MANIPULATE CERTAIN CONDITIONS IN THE CELL'S ENVIRONMENT. LASTLY, WE PLAN TO USE CUTTING-EDGE GENOMICS APPROACHES TO EVALUATE THE GENETIC SIGNATURE OF THESE CELLS AT THE INDIVIDUAL LEVEL, WHICH WILL ALLOW US TO DETERMINE JUST HOW DIFFERENT THESE CELLS ARE, AND WHETHER THEY HAVE A GREATER "POTENTIAL" TO PRODUCE MILK AS PART OF A NORMAL LACTATION.