Final answer:
Deletions in DNA are not always lethal, and their impact varies depending on their size, location, and the genetic makeup of the individual. While some deletions can lead to severe conditions like Huntington's disease, others might not significantly affect an individual's ability to survive or reproduce. Mutations can have a wide range of effects, from detrimental to beneficial.
Step-by-step explanation:
Deletions are not always lethal events. They can have varying effects depending on the size of the deletion and its location in the genome. For example, Huntington's disease is caused by a dominant lethal allele that does not always manifest until middle age, after individuals have had the chance to reproduce. Hence, such a dominant lethal allele can be passed on to offspring, maintaining it in the population. Not all deletions are as critical; some may result in a shortened life span or medical complications, while others might not significantly affect an organism's survival or ability to reproduce.
Furthermore, it's important to note that smaller deletions might not be detrimental if they occur in non-critical regions of the DNA. Conversely, larger deletions that eliminate several genes can have more severe consequences. Mutations like insertions or deletions can be more detrimental than point mutations because they can result in a frameshift, changing the amino acid sequence for a protein downstream of the mutation and potentially disabling the protein's function. However, not all mutations or chromosomal alterations result in negative outcomes; some might even increase an organism's fitness in its particular environment.