• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Gene mutations

Extracts from this document...

Introduction

Gene mutations What is a gene mutation? Sudden and spontaneous changes in phenotype, for which there are no conventional genetic explanations or any microscopic evidence of chromosomal mutation, can only be explained in terms of changes in gene structure. A gene mutation or point mutation (since it applies to a particular gene locus) is the result of a change in the nucleotide sequence of the DNA molecule in a particular region of the chromosome. Such a change in the base sequence of the gene is transmitted to mRNA during transcription and may result in a change in the amino acid sequence of the polypeptide chain produced from it during translation at the ribosomes. ...read more.

Middle

Somatic mutations are probably very common and go unnoticed, hut in some cases they niay produce cells with an increased rate of growth and division. These cells may give rise to a tumour which may be benign and not affect other tissues, or malignant, which live parasitically on healthy cells, a condition known as cancer. The effects of gene mutation are extremely variable. Most minor gene mutations pass unnoticed in the phenotype since they are recessive, but there arc several cases where a change in a single base in the genetic code can have a profound effect on the phenotype. Sickle cell anaemia in humans is an example of base substitution mutation affecting a base in one of the genes involved in the production of hacmoglobin. ...read more.

Conclusion

Gene reshuffling as a result of crossing-over, independent assortment, random fertilisation and mutations, may increase the amount of continuous variation but the evolutionary implications of this are often short-lived since the changes produced may be rapidly diluted. Certain gene mutations, on the other hand, increase discontinuous variation and this has the more profound effect on changes in the population. Most gene mutations are recessive to the 'normal' allele which has come to form genetic equilibrium with the rest of the genotype and the environment as a result of successfully withstanding selection over many generations. Being recessive the mutant alleles may remain in the population for many generations until they come together in the homozygous condition and are expressed phenotypically. Occasionally a dominant mutant allele may arise in which case it will appear imniediately in the phenotype. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Genetics, Evolution & Biodiversity section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Genetics, Evolution & Biodiversity essays

  1. Marked by a teacher

    An Investigation into the Mitotic Nuclear Division of Allium Sativum Root Tip Cells, and ...

    5 star(s)

    Using the Bunsen heating equipment, it is greatly difficult to regulate a constant, suitable temperature when heating the sample and staining solution. It is for staining solution heats in a somewhat unpredictable manner, and has the potential to damage the tissue sample.

  2. Mutation and its Consequences - Gene mutations occur when there is change in the ...

    Some amino acids are coded by several different codons, so there may not be a change in the amino acid. The mutation may be beneficial. The new amino acid may alter the protein in a way that is beneficial to the organism.

  1. The Biology of Autistic Spectrum Disorder and the Social Implications

    that the exact causes of ASD are still unknown, even though some research has shown that a faulty gene may be involved, which could have been inherited from one or both parents. ASD is also a condition that will continue throughout life, though there is some evidence to suggest that

  2. An Investigation into the effect of flow rate on the size of Gammarus pulex

    In the pilot study, a wrist watch was used instead to record the time taken for the impellor to move from one end to another. This introduced errors as it was difficult to read the seconds off the wrist watch.

  1. Investigating the colour variation of Littorina littoralis and their abundance across the upper, middle ...

    To overcome this, there were multiple days possible to take the investigation, and using local weather forecasts, the most appropriate day was chosen. In this investigation, there were others around undergoing similar investigations. Each action may have affected other people's investigation in ways that may be damaging to both their results and welfare.

  2. Gm foods and Gene therapy

    issues, and if they believe that it does, they request opinion form an Advisory Group, which includes bioethicists. The set could then apply for extra information from the researcher(s) before reporting to BBSRC. latest grantholders are necessary to think social implications of their work and to remark upon them, plus

  1. Investigating the effect of trampling on salt marsh

    I also was more confident in using the clinometer gun. Apparatus- * Ranging Poles (� 2) * Clinometers * Measuring tape * Square Quadrat * Trowel * Small plastic collection bags * Protective clothing and wellington boots * pH test strip * Salinity meter * Filter paper * Evaporating dish

  2. patterns of growth and development

    They can get a object without having it being put into their hand. They enjoy banging toys on tables, crumpling paper, splashing in the bath and playing with their toes when on their backs. They use the whole hand to hole something.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work