Functional test of PCDHB11, the most human-specific neuronal surface protein

Table 1 Proteins on the surface of central nervous system cells that have accumulated the highest number of amino acid substitutions on the human lineage

Protein	Substitutions	Length of protein	Subst./length	Weighted subst.	Weighted subst./length
PCDHB11	12	797	0.015	89	0.112
ICAM1	6	532	0.011	41	0.077
HTR3E	4	456	0.009	33	0.072
HRH1	5	487	0.010	31	0.064
DRD5	5	477	0.010	30	0.063
PCDHB13	6	798	0.008	47	0.059
GLRA4	4	417	0.010	24	0.058
HOME3	2	361	0.006	19	0.053
PCDHB6	5	794	0.006	40	0.050
VIPR1	2	457	0.004	20	0.044
CCKAR	2	428	0.005	18	0.042
PCDHB12	4	797	0.005	30	0.038
OXYR	3	389	0.008	14	0.036
GRIN3A	6	1115	0.005	38	0.034
PCDHB10	3	797	0.004	27	0.034
SEMA5B	5	1151	0.004	32	0.028
PCDHA5	4	936	0.004	26	0.028
PCDHB14	4	798	0.005	21	0.026
GRIN2C	4	1236	0.003	32	0.026
PCDHA2	4	948	0.004	23	0.024
CD44	3	742	0.004	17	0.023
PCDHB15	4	787	0.005	18	0.023
PCDH15	9	1955	0.005	43	0.022

For each protein, the number of human-specific substitutions, divided by the length of the protein, gives the fraction of amino acids that have changed and become fixed on the human lineage. For each amino acid substitution on the human lineage, a weight was derived from the BLOSUM100 matrix that reflects the rareness of this exchange between organisms that have 99 % amino acid identity, and the weights of all substitutions were summed up for each protein

ISSN: 2730-7182