Question

1. Describe the role of gene duplication which leads to the evolution of autologous genes within a gene family. What are some of the benefits of having such a family? What might be some drawbacks from a research perspective?
2. Describe the evolution of the expressive eye phenotype of domesticated dogs that is distinct from ancestral wolves. Which structures give dogs these expressive eyes? What was the purpose/advantage of the adaptation? How did humans likely provide the driving force for this evolution to occur?
3. After the drought of 1977, researchers hypothesized that on the Galápagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of the following would be most likely to occur to finch beaks on this island? Increased variation in beak size and shape over time OR Decreased variation in beak size and shape over time. Why?

These are about evolution and genetics. Please explain!

Answer 1

Autologous genes can perform similar functions or enhance the efficiency of action by creating complexes of autologous proteins. This is observed in the globin family of proteins. The beta-globin and alpha-globin genes are autologous and gove rise to the hemoglobin molecule. Both alpha and beta proteins are needed in hemoglobin for optimal oxygen uptake. Lack of either one of them results in less efficiency of action and in the case of globins lack of either of them results in thalassemia diseases.

In the research perspective, the autologous genes create problems in gene functional analysis studies. In order to study role of a gene, scientists have to remove inactivate all similar copies to create a null mutation. Otherwise, gene redundancy will ruin their experiment.

Dogs are more domesticated animals than wolves. It is human tendency to develop a compassionate attitude towards organisms that can convey their emotions through expressions. This might have supported the dogs with eyebrows and similar structures that convey expression to get selected and result in evolution. Later humans have created many artificial dog breeds by selecting their mates to generate dogs with special characters like aggression, good fur, etc.

In the Galápagos Island Daphne Major, the beak diversity of medium ground finches will increase as seeds of large size variation are available for birds to eat now. If only particular beak size is available, only birds wich can crack and eat that seed would have survived. However, since all the birds with different beak sizes will be getting seeds that they are able to crack and eat, the current beak diversity will sustain and diversify more if more types of seeds are introduced.