关键词:
摘要: Frequent recombination occurs during replication in all retroviruses examined. This increases the genetic variation retroviral population and may be of importance evolution virus. Maedi-visna virus (MVV), a retrovirus sheep, has highly variable envelope gene. In previous experiment, 20 sheep were infected with an uncloned strain MVV was isolated at regular intervals for 7 years. We sequenced genes number these strains found evidence that have contributed to observed high frequency antigenic variants.