Unusual linkage patterns of ligands and their cognate receptors indicate a novel reason for non-random gene order in the human genome

Table 1 Incidences of occurrence, on the same human chromosome, of a ligand with one of its cognate receptors after removal of tandem duplicates by Blast and by the physical proximity method. The distance is defined as the span between the mid-positions of the ligand and the mid-position of the receptor.

Class	Gene	Unigene #	Cytogenetic	Distance (Mb)
Ligand	DLL1	368657	6q27
Receptor	NOTCH4	436100	6p21.3	138.23
Ligand	DLL3	127792	19q13
Receptor	NOTCH3	8546	19p13.2-p13.1	29.53
Ligand	EFNA4	449913	1q21-q22
Receptor	EPHA8	283613	1p36.12	129.2
Ligand	TNFSF18	248197	1q23
Receptor	TNFRSF18	212680	1p36.3	168.57
Ligand	IL1RN	81134	2q14.2
Receptor	IL1R2	25333	2q12-q22	11.51
Ligand	HGF	396530	7q21.1
Receptor	MET	419124	7q31	34.96
Ligand	MST1	349110	3p21
Receptor	MST1R	2942	3p21.3	0.21
Ligand	FGF1	278954	5q31
Receptor	FGFR4	165950	5q35.1-qter	34.45
Ligand	FGF2	422889	4q26-q27
Receptor	FGFR3	1420	4p16.3	122.37
Ligand	FGF8	57710	10q24
Receptor	FGFR2	404081	10q26	19.77
Ligand	FGF10	248049	5p13-p12
Receptor	FGFR4	165950	5q35.1-qter	132.07
Ligand	FGF17	248192	8p21
Receptor	FGFR1	748	8p11.2-p11.1	16.46
Ligand	FGF18	87191	5q34
Receptor	FGFR4	165950	5q35.1-qter	5.65
Ligand	VEGFC	79141	4q34.1-q34.3
Receptor	KDR	12337	4q11-q12	122.23
Ligand	PTN	44	7q33-q34
Receptor	PTPRZ1	78867	7q31.3	15.23
Ligand	TGFB2	169300	1q41
Receptor	TGFBR3	342874	1p33-p32	122.99
Ligand	BMP3	121507	4p14-q21
Receptor	BMPR1B	480321	4q22-q24	13.97
Ligand	BMP10	158317	2p13.3
Receptor	ACVR1	150402	2q23-q24	89.45
Receptor	ACVR2	283349	2q22.2-q23.3	79.47
Ligand	INHBB	1735	2cen-q13
Receptor	ACVR1	150402	2q23-q24	37.64
Receptor	ACVR2	283349	2q22.2-q23.3	27.66
Ligand	INHA	407506	2q33-q36
Receptor	ACVR1	150402	2q23-q24	61.8
Receptor	ACVR2	283349	2q22.2-q23.3	71.79
Ligand	TF	433923	3q22.1
Receptor	TFRC	185726	3q29	62.32
Ligand	APOE	110675	19q13.2
Receptor	LDLR	213289	19p13.3	39.02

ISSN: 2730-7182