Genetic load

Genetic load is the difference between the fitness of the theoretically optimal genotype and the fitness of the observed average genotype in a population. This means that populations with a low genetic load will tend to be healthier, have fitness that is less dispersed, and have offspring that are more likely to survive to reproduction. On the other hand, populations with a high genetic load will have a greater variance in fitness levels; furthermore, a population with a high genetic load is not likely to have as many organisms at or near the optimal fitness. Genetic load can be viewed as the probability that an organism will fail to reach its reproductive age. This is important to scientists because if genetic load gets too high the population will be in danger of going extinct because the organisms are not able to survive and reproduce.