This has been estimated at anything from 35,000 to 150,000. This led to an interesting debate on the definition of a gene and how to assess that number. A gene is a set of connected transcripts. Two transcripts are connected if they share at least part of one exon in the genomic coordinates. At least one transcript must be expressed outside of the nucleus and one transcript must encode a protein.
More surprises seem sure to be in store.
The Human Gene Nomenclature Committee is the accepted authority for establishing these standards. Genetic maps have been used to find the exact chromosomal location of several important disease genes, including cystic fibrosis, sickle cell disease, Tay- Sachs disease, fragile X syndrome, and myotonic dystrophy. Starting genetic maps is easier than finishing them. A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g. an antigen binding to an antibody , a hormone or neurotransmitter binding to a receptor , or a substrate or allosteric effector binding to an enzyme . Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex.