Welcome back to blogging! This week we will be focusing on how changes in DNA affect individuals across different populations. To help us complete this complex work, we will be using our blog as a place to answer specific questions about chromosomal mutations. At the end of reading, choose ONE question to write a response on:
- HOW IS MEIOSIS AND MITOSIS RELATED TO CHROMOSOME MUTATIONS
- HOW DO CHANGES IN CHROMOSOMES AFFECT A HUMAN BEING?
- BASED OFF YOUR PREVIOUS RESEARCH, HOW DO THE SYMPTOMS RELATED TO CHROMOSOMAL MUTATIONS AFFECT AN INDIVIDUAL?
- HOW IS MEIOSIS AND MITOSIS RELATED TO CHROMOSOME MUTATIONS
- HOW DO CHANGES IN CHROMOSOMES AFFECT A HUMAN BEING?
- BASED OFF YOUR PREVIOUS RESEARCH, HOW DO THE SYMPTOMS RELATED TO CHROMOSOMAL MUTATIONS AFFECT AN INDIVIDUAL?
Chromosome Mutation
A chromosome mutation is an unpredictable change that occurs in a chromosome. These changes are most often brought on by problems that occur during meiosis (cell division process of gametes) or by mutagens (chemicals, radiation, etc.). Chromosome mutations can result in changes in the number of chromosomes in a cell or changes in the structure of a chromosome. Unlike a gene mutation which alters a single gene or larger segment of DNA on a chromosome, chromosome mutations change and impact the entire chromosome.
Please note that we are only talking about the chromosome changes. We do not need to worry about point mutations yet.
Chromosome Structure Changes
Duplications and breakages of chromosomes are responsible for a type of chromosome mutation that alters chromosome structure. These changes affect protein production by changing the genes on the chromosome. Chromosome structure changes are often harmful to an individual leading to developmental difficulties and even death. Some changes are not as harmful and may have no significant effect on an individual. There are several types of chromosome structure changes that can occur. Some of them include:Chromosome Number Changes
A chromosome mutation that causes individuals to have an abnormal number of chromosomes is termedaneuploidyAneuploid cells occur as a result of chromosome breakage or nondisjunction (non-separatin) errors that happen during meiosis or mitosis. Nondisjunction is the failure of homologous chromosomes to separate properly during cell division. It produces individuals with either extra or missing chromosomes. Sex chromosome abnormalities that result from nondisjunction can lead to conditions such as Klinefelter and Turner syndromes. In Klinefelter syndrome, males have one or more extra X sex chromosomes. In Turner syndrome, females have only one X sex chromosome. Down syndrome is an example of a condition that occurs due to nondisjunction in autosomal (non-sex) cells. Individuals with Down syndrome have an extra chromosome on autosomal chromosome 21.A chromosome mutation that results in individuals with more than one haploid set of chromosomes in a cell is termedpolyploidy. A haploid cell is a cell that contains one complete set of chromosomes. Our sex cells are considered haploid and contain 1 complete set of 23 chromosomes. Our autosomal cells are diploid and contain 2 complete sets of 23 chromosomes. If a mutation causes a cell to have three haploid sets, it is called triploidy. If the cell has four haploid sets, it is called tetraploidy. People who suffer from Down Syndrome can be said to have a triploidy because they have an extra chromosome.
Now that you have read and discussed this post, choose one of the following questions and write a 3-5 sentence response:
- HOW IS MEIOSIS AND MITOSIS RELATED TO CHROMOSOME MUTATIONS
- HOW DO CHANGES IN CHROMOSOMES AFFECT A HUMAN BEING?
- BASED OFF YOUR PREVIOUS RESEARCH, HOW DO THE SYMPTOMS RELATED TO CHROMOSOMAL MUTATIONS AFFECT AN INDIVIDUAL?
