Flour beetles, Tribolium castaneum, are easy to keep and widely used as laboratory animals. They consume wheat and other grains while being adapted to survive in very dry environments. The flour beetles are major pests in the agricultural industry, in particular cereal silos, and are highly resistant to insecticides.An experiment was conducted over 20 generations using different populations of flour beetles over 20 generations. Using breakfast cereal as a food source, two different populations of 10 (figure 1) and 100 (figure 2) were studied with each beetle being heterozygous for alleles b+ and b alleles. The frequency of the b+ allele was measured in the population after every generation.1. What is the dependent variable? What is the control negative group? ### Genetic Drift Experiment on Beetle Populations**Graph Descriptions:**The graphs depict experimental results on the genetic drift of beetle populations over 20 generations, focusing on the frequency of a specific allele, b+.**Graph A:**- This graph represents the genetic drift in beetles when the population size is maintained at 10 beetles. - The y-axis shows the frequency of the b+ allele, ranging from 0% to 100%.- The x-axis represents the number of generations, from 0 to 20.- Multiple lines indicate separate population trials, displaying significant fluctuations in allele frequency over time.- Notably, in one population, the b+ allele is lost entirely (indicating by a line ending at 0%).**Graph B:**- This graph shows the results when the population size is maintained at 100 beetles.- Similar to Graph A, the y-axis indicates the frequency of the b+ allele and the x-axis shows generations from 0 to 20.- The lines are flatter compared to Graph A, suggesting less pronounced fluctuations in allele frequency.- The b+ allele is more consistently present in these larger populations, indicating less impact from genetic drift.**Analysis:****A.** In smaller populations (10 beetles), genetic drift plays a significant role, often leading to the loss of alleles in some populations due to random changes over generations.**B.** In larger populations (100 beetles), the effect of genetic drift is minimized, resulting in more stable allele frequencies over the same number of generations. This illustrates how increased population size can mitigate the random effects of genetic drift, maintaining genetic diversity.

Genetic drift is a process in which allele frequencies within a population change by chance alone as a result of sampling error from generation to generation. Genetic drift is a random process that may result in large changes in populations over a short period of time. Random drift is caused by decreasing the small population sizes, severe reductions in population size called "bottlenecks" and founder events where a new population starts from a small number of individuals. Genetic drift leads to fixation of alleles or genotypes in populations. Drift increases the inbreeding coefficient and increases homozygosity as a result of removing alleles. It is believed that drift is probably common in populations that undergo regular cycles of extinction and recolonization. 1. Population size is the dependent variable in the above experiment because population size will affect the allelic frequency present in a population. 2. Group b with population size of 100 should be considered as the control.