Dog Vaccination Schedule. Age. Vaccination. 5 weeks. Parvovirus: for puppies at high risk of exposure to parvo, some veterinarians recommend vaccinating at 5 weeks. Check with your veterinarian. 6 & 9 weeks. Combination vaccine * without leptospirosis.*Some puppies may need additional vaccinations against parvovirus after 15 weeks of age. Consult with your local veterinarian. Â§ According to the American Veterinary Medical Association, dogs at low risk of disease exposure may not need to be boostered yearly for most diseases.
In population genetics, directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
Selection Bias Selection bias is defined as a bias when the subjects, groups or data is selected for the analysis is not randomly selected and forms a non representative sample of the given population. In other words, selection bias occurs where there is no randomization while selecting a sample and thus the selected sample is not a representative sample for the population. It is also known as selection effect. Some of the examples of selection bias are given below: