Abstract: Methods are described for mapping a pathway of differentiation of a population of embryonic cells that includes exposing the cells to an exogenous factor and measuring gene expression products that are characteristic of a particular cell type or lineage. Directing differentiation of human embryonic cells relies on dissociated embryoid bodies that are then exposed to one or more exogenous factors to enrich a culture for a particular cell type. The differentiated cells may be used for treating a medical condition in a human. Kits for determining differentiation pathways and screening exogenous factors for their utility in differentiation are provided.

Abstract: Methods are described for mapping a pathway of differentiation of a population of embryonic cells which includes exposing the cells to an exogenous factor and measuring gene expression products that are characteristic of a particular cell type or lineage. Directing differentiation of human embryonic cells relies on dissociated embryoid bodies which are then exposed to one or more exogenous factors to enrich a culture for a particular cell type. The differentiated cells may be used for treating a medical condition in a human. Kits for determining differentiation pathways and screening exogenous factors for their utility in differentiation are provided.

Abstract: The invention relates to a method of preparing from human embryonic stem cells, differentiated cells suitable for transplantation, by introducing human embryonic stems cells into an avian host embryo. Also provided is a method of directing the differentiation of human embryonic stem cells by introducing them into a selected location in an avian host embryo, which dictates their differentiation pattern. The invention provides normal, transplantable differentiated human cells, e.g. progenitor and other cells, particularly neural cells. The invention also relates to therapeutic and diagnostic methods employing the differentiated cells of the invention.

Abstract: Methods are described for mapping a pathway of differentiation of a population of embryonic cells which includes exposing the cells to an exogenous factor and measuring gene expression products that are characteristic of a particular cell type or lineage. Directing differentiation of human embryonic cells relies on dissociated embryoid bodies which are then exposed to one or more exogenous factors to enrich a culture for a particular cell type. The differentiated cells may be used for treating a medical condition in a human. Kits for determining differentiation pathways and screening exogenous factors for their utility in differentiation are provided.

Abstract: Methods are provided for altering gene expression in a population of human embryonic cells that include introducing a gene expression altering sequence into cells the cells retaining their pluripotent character, for purifying pluripotent embryonic stem cells from a heterogeneous population of cells, and for treating a human suffering from a deficiency of a selected cell type. Reagent cell populations are further provided for supplying material for transplantation consisting essentially of pluripotent human embryonic stem cells modified by foreign genetic material.