To be of a line or ancestry (of people with a certain characteristic); stock, breed (of animals); strain (of plants).
               
               
               
               Such as generations of relatives; descendants of a social class or one particular person.
               
               
                  
                  
                  
                  This water buffalo of mine is of a stock of big water buffalos.
                  
                
               
               
                  
                  
                  
                  That person is of a line of imams.
                  
                
               
               
                  
                  
                  
                  That person is of an ancestry of rich people.
                  
                
               
               
                  
                  
                  
                  This papaya is of a strain of big (lit. American) papayas.