Albinism, caused by a mutational disruption in melanin (skin pigment) production, has been observed in many species, including humans. In 1991, and again recently in 2017, the only documented observations of an albino humpback whale (named 'Migaloo') were observed near New South Wales. Recently, Polanowski and coworkers (Polanowski, A., S. Robinson-Laverick, and D. Paton. (2012). Journal of Heredity 103:130–133) studied the genetics of humpback whales from the east coast of Australia, including Migaloo. Do you think that Migaloo's albinism is more likely caused by a dominant or recessive mutation? Explain your reasoning.

Verified step by step guidance

1. Understand the basic genetics of albinism: Albinism is typically caused by a mutation that disrupts melanin production, which is often due to a recessive allele.
2. Consider the inheritance pattern: If albinism were caused by a dominant mutation, we would expect to see more albino individuals in the population, as only one copy of the dominant allele would be needed to express the trait.
3. Evaluate the rarity of the trait: Since Migaloo is one of the very few documented albino humpback whales, this suggests that albinism is rare in this population, which is more consistent with a recessive mutation.
4. Analyze the implications of a recessive mutation: For a recessive trait to be expressed, an individual must inherit two copies of the recessive allele, one from each parent, which aligns with the rarity of the trait.
5. Conclude based on genetic principles: Given the rarity and typical inheritance patterns of albinism, it is more likely that Migaloo's albinism is caused by a recessive mutation.

Key Concepts

Genetic Mutations

Genetic mutations are changes in the DNA sequence that can affect how genes function. These mutations can be classified as dominant or recessive, depending on how they influence the phenotype when present in an organism. A dominant mutation will express its trait even if only one copy is present, while a recessive mutation requires two copies for the trait to be expressed.

Albinism and Melanin Production

Albinism is a genetic condition characterized by a lack of melanin, the pigment responsible for coloration in skin, hair, and eyes. This condition arises from mutations in genes involved in melanin production, such as the TYR gene. Understanding the genetic basis of albinism helps in determining whether the trait is likely to be inherited as dominant or recessive.

Inheritance Patterns

Inheritance patterns describe how traits are passed from parents to offspring, influenced by the genetic makeup of the parents. In the case of albinism, if the trait is caused by a recessive mutation, both parents must carry the mutation for their offspring to express albinism. Conversely, if it is caused by a dominant mutation, only one parent needs to pass on the mutated gene for the offspring to exhibit the trait.