give three examples of a newly expressed trait that could help an organism and three  of newly expressed trait that can harm an organism (3 and 3i is 6 total).

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trophyhunter1 eNotes educator| Certified Educator

Mutations are changes in a gene for a particular trait. Sometimes a mutation can be beneficial. For example, in humans(usually of European descent) a base pair deletion in the gene CCR5 confers resistance to HIV in homozygotes and delayed AIDS onset in heterozygotes. This mutation was probably one that gave resistance to people during the years of the bubonic plague in the 14th century. Another example is the Sickle cell gene in Sub-Saharan people where Malaria is prevalent. In these people, being heterozygous(one normal and one sickle cell gene) gives them protection about the Malaria plasmodium in mosquitoes. Malaria in these countries kills millions of people per year.  Additionally, Cystic Fibrosis gene is an autosomal recessive disease of the lungs and sweat glands and digestive organs. In the homozygous condition, it shortens life span, but in the heterozygous condition it is believed it conferred a resistance to cholera which throughout European history, killed many people. It also protected against losing body fluid lost when a person developed diarrhea. Harmful mutations affect organisms by making them less fit. They can cause conditions or diseases in the organism. One example is Huntington's disease. It is autosomal dominant gene which means an individual with one copy of this gene will develop the condition. It is adult onset and leads to cognitive decline and psychiatric problems and death. Hereditary nonpolyposis colorectal cancer is another mutation which increases one's risk of colorectal, brain, skin, ovarian and other cancers. Albinism is a genetic mutation which is recessive. It is harmful because melanin in the skin protects one from the sun's harmful rays. People with this mutation are more prone to skin cancer and have sensitive eyes because they do not produce melanin.

akih081 | Student

3 examples of a trait that could help an organism: -

1. A skin pattern or coloration that matches the organism's current environment for enhanced camouflage

2. Lengthening or other modification of a body that is essential in gathering food (i.e. longer necks in giraffes)

3. Stronger beaks in a parrot population where nuts have become harder to crack


3 examples of a trait that could harm an organism:-

1. Extra appendages appearing in amphibians

2. Albinism- causes animals to be visible to predators and/or prey

3. Weakening in bone structure of large land-based animals

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