Mutation
What is Mutation?
An offspring may show characteristics that are not seen in either parent nor in family history. The chances of this happening is most likely to result from mutation. Not all mutations are harmful, but there are many that are. There are two main types of mutation:
Gene mutation- changes in a single gene so that the traits that are normally produced by the gene are changed or destroyed. This usually occurs during the replication of the DNA molecule before cell division.
Chromosomal mutations- the whole chromosome is affected.
Website: http://evolution.berkeley.edu/evolibrary/article/mutations_01
An offspring may show characteristics that are not seen in either parent nor in family history. The chances of this happening is most likely to result from mutation. Not all mutations are harmful, but there are many that are. There are two main types of mutation:
Gene mutation- changes in a single gene so that the traits that are normally produced by the gene are changed or destroyed. This usually occurs during the replication of the DNA molecule before cell division.
Chromosomal mutations- the whole chromosome is affected.
Website: http://evolution.berkeley.edu/evolibrary/article/mutations_01
Mutagens
There are a number of agents that are known to increase the rate in which mutation occurs. This is known as mutagenic agents or mutagens. Mutagens do not necessarily cause defects but more so increase the rate at which mutations take place. ultraviolet rays, x-rays, cosmic rays and radiation are all classed as mutagens.
video: http://www.youtube.com/watch?v=oTJcBJhTDNo
There are a number of agents that are known to increase the rate in which mutation occurs. This is known as mutagenic agents or mutagens. Mutagens do not necessarily cause defects but more so increase the rate at which mutations take place. ultraviolet rays, x-rays, cosmic rays and radiation are all classed as mutagens.
video: http://www.youtube.com/watch?v=oTJcBJhTDNo
Somatic and germline mutations
Somatic mutation refers to the DNA change that occurs in body cells besides germ (sex) cells. These mutations cannot be passed onto the offspring. Somatic mutations are involved in many cancerous growths and may be a result of a mutagenic agent.
Germinal or germline mutations are if the sex cells are affected. In this case the individual who carries it isn't so much affected but the offspring created can have this mutation. If conception occurs and the embryo is carrying the mutated genes then it is often naturally aborted. In some cases mutations are not harmful and can actually have some definite advantages.
website: http://www.cancer.gov/cancertopics/understandingcancer/cancergenomics/page10
Somatic mutation refers to the DNA change that occurs in body cells besides germ (sex) cells. These mutations cannot be passed onto the offspring. Somatic mutations are involved in many cancerous growths and may be a result of a mutagenic agent.
Germinal or germline mutations are if the sex cells are affected. In this case the individual who carries it isn't so much affected but the offspring created can have this mutation. If conception occurs and the embryo is carrying the mutated genes then it is often naturally aborted. In some cases mutations are not harmful and can actually have some definite advantages.
website: http://www.cancer.gov/cancertopics/understandingcancer/cancergenomics/page10
Effects of mutations
Gene mutations:
When it became apparent that genetic information was contained in the sequence of bases in the DNA, it became easier to understand how mutations occurred. A change in just one base is known as point mutation. This could change one protein and have no effect at all or not allowing a protein to be produced. Just one missing or abnormal protein that results from this can have an enormous effect in the body. One example is albinism, which is marked by an absence of pigment from the hair, skin and eyes. The hair of the person being extremely blonde and the effected person has very pale skin.
lethal recessives:
Most gene mutations produce a recessive allele because they prevent a protein from being able to function in the body and therefore could have a large number of mutations and be unaware of them. However, if they were to reproduce with a partner with the same recessive mutation then this recessive trait can possibly be passed onto the offspring. An example of this is Tay-Sachs disease (TSD). This is a disorder of lipid metabolism that is inherited in an autosomal recessive pattern. This condition results in fatty substance build up in the nervous system due to a missing enzyme. A child with two recessive alleles usually die from deterioration causing mental and physical disabilities.
Website: http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation
Chromosomal mutations:
Chromosomal mutations affect all part of a chromosome and thus a number of genes as well. Types of chromosomal mutations are:
deletions-loss of a part of a chromosome
duplications-where a section of chromosome occurs twice
inversion- where a break occurs but the broken part reattaches the wrong way around
translocations- where part of a chromosome breaks off and is re-joined to the wrong chromosome
non-disjunctions- where during meiosis a chromosome pair do not separate.
video: http://www.youtube.com/watch?v=XAGxp9j5rtc
Gene mutations:
When it became apparent that genetic information was contained in the sequence of bases in the DNA, it became easier to understand how mutations occurred. A change in just one base is known as point mutation. This could change one protein and have no effect at all or not allowing a protein to be produced. Just one missing or abnormal protein that results from this can have an enormous effect in the body. One example is albinism, which is marked by an absence of pigment from the hair, skin and eyes. The hair of the person being extremely blonde and the effected person has very pale skin.
lethal recessives:
Most gene mutations produce a recessive allele because they prevent a protein from being able to function in the body and therefore could have a large number of mutations and be unaware of them. However, if they were to reproduce with a partner with the same recessive mutation then this recessive trait can possibly be passed onto the offspring. An example of this is Tay-Sachs disease (TSD). This is a disorder of lipid metabolism that is inherited in an autosomal recessive pattern. This condition results in fatty substance build up in the nervous system due to a missing enzyme. A child with two recessive alleles usually die from deterioration causing mental and physical disabilities.
Website: http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation
Chromosomal mutations:
Chromosomal mutations affect all part of a chromosome and thus a number of genes as well. Types of chromosomal mutations are:
deletions-loss of a part of a chromosome
duplications-where a section of chromosome occurs twice
inversion- where a break occurs but the broken part reattaches the wrong way around
translocations- where part of a chromosome breaks off and is re-joined to the wrong chromosome
non-disjunctions- where during meiosis a chromosome pair do not separate.
video: http://www.youtube.com/watch?v=XAGxp9j5rtc
Glass, K. (n.d.). chromosomal_mutations . Retrieved october 9, 2014, from YouTube: http://www.youtube.com/watch?v=XAGxp9j5rtc
Mutations: Somatic and Germline. (n.d.). Retrieved october 9, 2014, from National Cancer Institute: http://www.cancer.gov/cancertopics/understandingcancer/cancergenomics/page10
VBS. (n.d.). Mutations: The start of the evolutionary process. Retrieved October 9, 2014, from http://staff.jccc.net/pdecell/evolution/mutations/mutation.html
What is a gene mutation and how do mutations occur? (n.d.). Retrieved October 9, 2014, from Genetics Home Reference: http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation
WhiteBoardScience. (n.d.). Mutagens and Carcinogens . Retrieved october 9, 2014, from Youtube: http://www.youtube.com/watch?v=oTJcBJhTDNo
Oh, J. (n.d.). Extra or Missing Chromosomes. Retrieved October 9, 2014, from The Tech: http://genetics.thetech.org/ask/ask296