Final answer:
Common methods for understanding the genetic basis of traits include genetic correlation studies within populations, direct genetic manipulation and observation of organisms, and microscopic studies of chromosomes correlated with offspring characteristics.
Step-by-step explanation:
The common methods for correlating specific characteristics to genes in organisms include genetic correlation between populations, which involves studying how selective forces change a population through changes in allele and genotypic frequencies. This method observes the genetic basis of population-wide traits and determines whether traits have a genetic basis. Another method is through direct manipulation of genes, such as inserting or removing a particular gene and then observing the organism for resultant phenotypic changes. Additionally, there are correlations between microscopic observations of chromosomal movement during gamete formation and the characteristics of offspring that can suggest links between certain genes and traits.
Our understanding of the genetics of inheritance began with Mendel's observations of allele inheritance in pea plants and has expanded to complex population genetics studies in diverse species. All the alleles in a population and their manifestation in observable traits – or phenotypic variation – are central to this field of study. An individual's traits are determined by the specific combination of inherited genes, and different alleles can account for much of the variation in the characteristics of organisms.