<Tr> <Th_colspan="10"> ABO allele frequencies in Korean, Japanese and German populations </Th> </Tr> <Tr> <Th> Population </Th> <Th_colspan="6"> ABO allele </Th> </Tr> <Tr> <Th> A (Pro) </Th> <Th> A (Leu) </Th> <Th> </Th> <Th> O (T) </Th> <Th> O (A) </Th> <Th> O </Th> </Tr> <Tr> <Td> Korean (n = 253) </Td> <Td> 0.022 </Td> <Td> 0.209 </Td> <Td> 0.209 </Td> <Td> 0.360 </Td> <Td> 0.200 </Td> <Td> 0 </Td> </Tr>

How does the abo blood typing system work