Tabby patterns were thought to be created by several alleles of one gene. Data collected from the cat fancy indicates that tabby patterns are probably caused by at least three separate genes with multiple alleles. 44555 Incidence of mediastinal lymphosarcoma in young FeLV-negative pedigreed Oriental Shorthair cats has been observed since the early 1980's. Affected cats are typically between 3 months and 2 years of age, and present initially with dyspnea or difficulty in eating. Characteristically further examination reveals a large mediastinal mass with metastases to surrounding lymph nodes.
Tumors grow rapidly and are quickly terminal unless treated.
Tumors regress rapidly in response to chemotherapy and there are currently a number of affected cats that have survived for a year or more with treatment. Pedigree analysis reveals that the vast majority of affected Oriental Shorthair's are descendants, on both their maternal and paternal sides, of a single male who died of lymphosarcoma in the early 1980's. A few affected cats have this line of descent form only one parent. Mechanisms of Human Mitochondrial DNA Replication . State University, USA, 3.