Gilliland studies chromosome segregation during female meiosis in Drosophila melanogaster in order to find out how homologous chromosomes coorient prior to the reductional first meiotic division. He uses genetic and cytological techniques in his research program to determine how often errors occur during meiosis and to try and identify what events cause those errors.

Gilliland WD, Hughes SF, Vietti DR, Hawley RS. Congression of achiasmate chromosomes to the metaphase plate in Drosophila melanogaster oocytes. Developmental Biology. 2009;325(1):122-8. Gilliland WD, Vietti DL, Schweppe NM, Guo F, Johnson TJ, Hawley RS. Hypoxia transiently sequesters mps1 and polo to collagenase-sensitive filaments inDrosophila prometaphase oocytes. PLoS ONE. 2009;4(10):e7544. Zeng Y, Li H, Schweppe NM, Hawley RS, Gilliland WD. Statistical Analysis of Nondisjunction Assays in Drosophila. Genetics. 2010;186(2):505-13. ?? Gillies SC, Lane FM, Paik W, Pyrtel K, Wallace NT, Gilliland WD. Nondisjunctional segregations in Drosophila female meiosis I are preceded by homolog malorientation at metaphase arrest. Genetics. 2012, in press.