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 genetic basis of albinism: Albinism is typically caused by mutations in genes involved in melanin production. These mutations often result in a loss of function of the gene product, which disrupts melanin synthesis.
2. Recall the difference between dominant and recessive mutations: A dominant mutation requires only one copy of the mutated allele to express the trait, while a recessive mutation requires two copies (homozygous) of the mutated allele for the trait to manifest.
3. Consider the rarity of albinism: Albinism is generally a rare condition, which suggests that it is more likely caused by a recessive mutation. This is because recessive traits are less likely to appear in a population unless both parents carry the mutated allele.
4. Apply this reasoning to Migaloo: If Migaloo's albinism were caused by a dominant mutation, it would be more likely to appear in other humpback whales in the population. The rarity of albinism in humpback whales supports the idea that it is caused by a recessive mutation.
5. Conclude based on genetic principles: Given the rarity of albinism and the typical inheritance patterns of loss-of-function mutations, it is more likely that Migaloo's albinism is caused by a recessive mutation rather than a dominant one.

Key Concepts

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 that regulate melanin production, leading to reduced or absent pigment. Understanding the biological basis of albinism is crucial for analyzing its inheritance patterns and implications in various species, including humans and whales.

Dominant vs. Recessive Mutations

Genetic mutations can be classified as dominant or recessive based on their expression in an organism. A dominant mutation only requires one copy of the mutated gene to manifest the trait, while a recessive mutation necessitates two copies for the trait to be expressed. This distinction is vital for predicting the inheritance of traits like albinism and understanding how they may appear in offspring.

Genetic Inheritance Patterns

Genetic inheritance patterns describe how traits and mutations are passed from parents to offspring. These patterns can be influenced by various factors, including whether a mutation is dominant or recessive. In the case of albinism in humpback whales, analyzing the inheritance patterns can help determine the likelihood of Migaloo's albinism being caused by a dominant or recessive mutation, impacting future generations.