A B C D E F G H I J K L M N O P Q R S T U V W X Y Z X Chromosome: one of the two sex chromosomes, X and Y. See also Y chromosome, sex chromosome. Xenogeneic (Heterologous): pertaining to individuals of different species. Xenograft (Heterograft): tissue or organs from an individual of one species transplanted into or grafted onto an organism of another species, genus, or family. A common example is the […]