Question

Match the terms appropriately. polyploid syndrome aneuploidy Mendelian genotype Huntington's disease a. symptoms of a genetic disorder b. extra sets of chromosomes c. caused by a short tandem repeat d. one extra chromosome e. dominant> recessive f. an individual's alleles

Short answer

1. b 2. a 3. d 4. e 5. f 6. c

Step-by-step solution

Identify the Meaning of Each Term

First, understand the meaning of each term: - Polyploid refers to having extra sets of chromosomes. - Syndrome generally indicates a group of symptoms that consistently occur together, pointing to a genetic disorder. - Aneuploidy is when there is one extra or missing chromosome. - Mendelian relates to genetic characteristics and inheritance based on Gregor Mendel's principles of dominance and recessiveness. - Genotype is the genetic makeup of an individual, specifically the set of alleles. - Huntington's disease is caused by repetition in a DNA sequence and follows a Mendelian pattern.

Match Each Term to Its Definition

Now, match each term with the appropriate definition: - Polyploid matches with (b) extra sets of chromosomes. - Syndrome matches with (a) symptoms of a genetic disorder. - Aneuploidy matches with (d) one extra chromosome. - Mendelian matches with (e) dominant > recessive. - Genotype matches with (f) an individual's alleles. - Huntington's disease matches with (c) caused by a short tandem repeat.

Verify the Matches

Ensure that each term is correctly matched by reviewing the definitions: - Polyploidy indeed involves additional sets of chromosomes, which matches with (b). - Syndromes involve a group of symptoms and link to (a). - Aneuploidy is known for an irregular number of chromosomes, especially one extra, hence (d). - Mendelian genetics is recognized for the dominant and recessive relationship, fitting with (e). - Genotype, relating to an individual's alleles, connects to (f). - The genetic defect in Huntington's disease is due to repeated DNA sequences, thus matching with (c).

Key concepts

Polyploidy

Polyploidy is a condition where an organism has more than two complete sets of chromosomes. While most animals are diploid, carrying two sets of chromosomes (one from each parent), some plants and a few animals can be polyploid. This means they have multiple sets, sometimes three (triploid), four (tetraploid), or even more.

Polyploidy is quite common in the plant kingdom and is a significant factor in plant evolution and diversity. It can lead to larger cell sizes and, consequently, larger plant organs. This trait is often seen in crops like wheat, cotton, and strawberries, which have been bred to enhance desired characteristics such as fruit size and hardiness.

• Polyploid plants often display increased robustness and adaptability.
• This condition can result from genome duplication events during cell division.
• In rare cases, some animal species exhibit polyploidy, notably certain amphibians, reptiles, and fish.

While polyploidy is less common in animals, it remains a fascinating aspect of genetics that plays a crucial role in the broader tapestry of biological evolution.

Aneuploidy

Aneuploidy occurs when an organism has an abnormal number of chromosomes, either having one extra or missing one. Unlike polyploidy, which involves full sets of chromosomes, aneuploidy involves individual chromosomes and usually results in serious developmental and health issues.

The most well-known example of aneuploidy in humans is Down syndrome, characterized by an extra chromosome 21. Other examples include Turner syndrome, where there is a missing X chromosome, and Klinefelter syndrome, with an extra X chromosome.

• Aneuploidy is often caused by errors in cell division, known as nondisjunction.
• It is a major cause of miscarriages and genetic disorders that appear at birth.
• Understanding aneuploidy is crucial for genetic counseling and prenatal diagnosis.

The study of aneuploidy highlights the delicate balance required for normal chromosome number and the potential consequences when this balance is disrupted.

Mendelian Genetics

Mendelian genetics is grounded in the principles first established by Gregor Mendel in the 19th century. These principles describe how traits are inherited through dominant and recessive alleles.

According to Mendelian genetics, for each inherited trait, an individual receives two alleles, one from each parent. If the alleles are different, the dominant one will mask the effect of the recessive allele. Thus, the trait associated with the dominant allele will be expressed.

• Principle of Dominance: Dominant alleles overshadow recessive ones when both are present.
• Segregation: Each parent's two alleles for a trait separate during gamete formation.
• Independent Assortment: Different pairs of alleles segregate independently of each other.

Mendel's work laid the foundation for genetics, revolutionizing our understanding of inheritance and trait expression. It remains a cornerstone in genetics education and research.

Genotype

The genotype of an individual refers to their specific genetic makeup, essentially the set of alleles they carry. This genetic composition influences various physical traits, known as the phenotype.

Genotype can be represented by notations like AA, Aa, or aa, where each letter represents an allele and the combination shows dominance or recessiveness.

• Genotypes determine potential traits but do not guarantee them due to environmental interactions.
• Analyzing genotypes is key in predicting inheritance patterns and potential genetic disorders.
• Genotype analysis can be used in personalized medicine to tailor treatments based on genetic predispositions.

Understanding the concept of genotype is essential for studying genetics, as it forms the basis for exploring how traits and genes are passed down across generations.

Huntington's Disease

Huntington's disease is a hereditary genetic disorder that affects the brain. It is caused by a mutation involving a repeating sequence of DNA bases, specifically the CAG trinucleotide, in the HTT gene. This repetition leads to the production of an abnormal protein that eventually causes nerve cells in the brain to break down.

It's crucial to understand that Huntington's disease follows a Mendelian pattern of inheritance, particularly autosomal dominant. This means that if one parent has the disease, their offspring have a 50% chance of inheriting the faulty gene and developing the disorder.

• The symptoms usually begin between the ages of 30-50 and worsen over time, leading to severe physical and cognitive decline.
• There's currently no cure, but treatments can help manage symptoms and improve quality of life.
• Genetic testing can confirm a diagnosis, and is also used for predictive testing in individuals with a family history of the disorder.

Knowledge about Huntington's disease not only aids in understanding this specific illness but also underscores the importance of genetics in diagnosing and managing hereditary diseases.