Genetic Variation and Evolution
38 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a limitation of RFLP?

  • Requires large amounts of high quality DNA (correct)
  • Is a highly efficient technique
  • Requires no special instrumentation
  • Can be automated

    • What is an advantage of RAPD?

  • Requires blotting and hybridization steps
  • Requires sequence information
  • Neither DNA probes nor sequence information is required (correct)
  • Requires DNA probes

    • What is a disadvantage of RAPD?

  • Reproducibility is high
  • It requires large amounts of DNA
  • It is a complex technique
  • Reproducibility is questionable (correct)

    • What is a characteristic of RAPD markers?

    <p>They are dominant markers</p> Signup and view all the answers

    What is a requirement for RFLP?

    <p>Large amounts of high quality DNA</p> Signup and view all the answers

    What is an advantage of RAPD over RFLP?

    <p>RAPD can detect higher levels of polymorphism</p> Signup and view all the answers

    What is a characteristic of RAPD primers?

    <p>They are universal and can be used for any species</p> Signup and view all the answers

    Why is RFLP use limited to specific laboratories?

    <p>It involves radioactive methods</p> Signup and view all the answers

    What is the maximum polymorphic information content for any bi-allelic marker?

    <p>0.5</p> Signup and view all the answers

    What type of repeats are commonly found in SSR markers?

    <p>Di-, tri-, and tetranucleotide repeats</p> Signup and view all the answers

    What is required for AFLP analysis?

    <p>High-quality DNA</p> Signup and view all the answers

    What is a limitation of AFLP markers?

    <p>They cluster densely in centromeric regions</p> Signup and view all the answers

    What is the name of the technique that combines polymorphism at RE sites and hybridization of arbitrary primers?

    <p>AFLP</p> Signup and view all the answers

    What is the size range of fragments amplified in AFLP?

    <p>50-150 bp</p> Signup and view all the answers

    What is necessary to score heterozygotes and homozygotes in AFLP?

    <p>Proprietary technology</p> Signup and view all the answers

    What is a type of variant of SSR markers?

    <p>Microsatellites</p> Signup and view all the answers

    What is the benefit of genetic variation in a population?

    <p>It increases the chance that some individuals will survive.</p> Signup and view all the answers

    What is the gene pool of a population?

    <p>All the alleles in a population.</p> Signup and view all the answers

    What is the result of mutation in a gene?

    <p>A new allele is formed.</p> Signup and view all the answers

    What is the result of recombination?

    <p>New combinations of alleles are formed.</p> Signup and view all the answers

    What is hybridization?

    <p>The crossing of two different species.</p> Signup and view all the answers

    What is the result of natural selection on a population?

    <p>Microevolution occurs.</p> Signup and view all the answers

    What is gene flow?

    <p>The movement of alleles between populations.</p> Signup and view all the answers

    What is the effect of low gene flow on populations?

    <p>It increases the chance that two populations will evolve into different species.</p> Signup and view all the answers

    What is the term used to describe the elimination of a species from Earth?

    <p>Extinction</p> Signup and view all the answers

    What is the primary focus of molecular phylogenetic analysis?

    <p>Analyzing evolutionary relationships between genes or species</p> Signup and view all the answers

    Which of the following DNA markers is used to recognize neutral variation at the DNA level?

    <p>RFLP</p> Signup and view all the answers

    What is the outcome of using RFLP in molecular linkage maps?

    <p>Accelerated the construction of molecular linkage maps</p> Signup and view all the answers

    What is the result of digesting purified DNA using restriction enzymes in RFLP?

    <p>RFLPs – a molecular fingerprint – unique to a particular individual</p> Signup and view all the answers

    Which of the following is an advantage of RFLP?

    <p>Simple methodology</p> Signup and view all the answers

    What is the name of the professor teaching the course 'Genes Evolution and Development'?

    <p>Prof. Dr. Mohamed El-Esawi</p> Signup and view all the answers

    In which year is the course 'Genes Evolution and Development' being taught?

    <p>2023-2024</p> Signup and view all the answers

    What is the characteristic of SSRs in terms of their mutation rate?

    <p>High, around 4x10^4 to 5x10^6 /allele/generation</p> Signup and view all the answers

    What is the mechanism behind SSR mutations?

    <p>Slipped strand miss pairing</p> Signup and view all the answers

    What is the advantage of SSR markers in terms of genotyping?

    <p>They have a high genotyping throughput</p> Signup and view all the answers

    What is the characteristic of SSRs in terms of their allelic variation?

    <p>High level of allelic variation</p> Signup and view all the answers

    What is the characteristic of SSRs in terms of their distribution in genomes?

    <p>Randomly dispersed throughout most genomes</p> Signup and view all the answers

    What is the characteristic of SSRs in terms of their reproducibility?

    <p>Reproducible</p> Signup and view all the answers

    Study Notes

    Genetic Variation

    • Genetic variation in a population increases the chance of some individuals surviving
    • Genetic variation leads to phenotypic variation, which is necessary for natural selection
    • Genetic variation is stored in a population's gene pool, made up of all alleles in a population
    • Allele frequencies measure genetic variation and can be calculated for each allele in the gene pool

    Sources of Genetic Variation

    • Mutation: a random change in the DNA of a gene that can form a new allele and be passed on to offspring
    • Recombination: forms new combinations of alleles, usually occurring during meiosis, and rearranges parents' alleles in new ways in gametes
    • Hybridization: the crossing of two different species, which can lead to new genetic variation

    Microevolution

    • Microevolution is evolution within a population, resulting in observable changes in allele frequencies
    • Natural selection can change the distribution of a trait in a population in one of three ways
    • Gene flow is the movement of alleles between populations, keeping neighboring populations similar

    Extinction

    • Species can become extinct, which is the elimination of a species from Earth
    • Background extinctions occur continuously at a low rate, usually affecting a few species in a small area due to local environmental changes

    Molecular Phylogeny and Markers Used for Measuring Genetic Variation

    • Molecular phylogenetic analysis is the study of evolutionary relationships between genes or species
    • DNA markers used for measuring genetic variation include:
      • RFLP (Restriction Fragment Length Polymorphism)
      • RAPD (Randomly Amplified Polymorphic DNA)
      • AFLP (Amplified Fragment Length Polymorphism)
      • SSR (Simple Sequence Repeat)

    RFLP

    • First used by Botstein et al. in 1980
    • Recognizes neutral variation at the DNA level, SNPs within a gene or between genes, and variable number of tandem repeats present between genes
    • Outcome: accelerated construction of molecular linkage maps, improved accuracy of gene location, and reduced time required to establish a complete linkage map
    • Technique: digestion of purified DNA using restriction enzymes, leading to the formation of RFLPs, a molecular fingerprint unique to a particular individual
    • Advantages: co-dominant, reproducible, simple methodology, and requires no special instrumentation
    • Limitations: requires large amounts of high-quality DNA, low genotyping throughput, difficult to automate, and involves radioactive methods

    RAPD

    • A single, random-sequence oligonucleotide primer in a low stringency PCR simultaneously amplifies several discrete DNA fragments
    • Outcome: several discrete DNA products up to 3 kb are amplified (amplicons), considered to originate from different genetic loci
    • Advantages: no DNA probes or sequence information required, no blotting or hybridization steps, small amounts of DNA required, can be automated, and detects higher levels of polymorphism than RFLP
    • Limitations: reproducibility is questionable due to factors such as PCR buffer, deoxynucleotide triphosphates (dNTPs), Mg2+ concentration, cycling parameters, source of Taq polymerase, and condition and concentration of template DNA primer concentration

    AFLP

    • Amplified fragment length polymorphism (Zabeau and Voss, 1993; Vos et al., 1995)
    • The selective PCR amplification of restriction fragments from a gDNA double-digest under high stringency conditions
    • Combination of polymorphism at RE sites and hybridization of arbitrary primers
    • 50 to 150 bp are amplified and polymorphism detected
    • Small DNA samples (1-100 ng) only required
    • Relatively reproducible across laboratories
    • Limitations:
      • Maximum polymorphic information content for any bi-allelic marker is 0.5
      • High-quality DNA is needed
      • Proprietary technology is needed to score heterozygotes and ++ homozygotes
      • AFLP markers cluster densely in centromeric regions in species with large genomes

    SSR

    • Variants: microsatellites, short tandem repeats (STRs), and sequence-tagged microsatellite sites (STMS)
    • Repeat Units 1-6 bp long
    • Di-, tri-, and tetranucleotide repeats – (CA)n, (AAT)n, and (GATA)n
    • Widely distributed in genomes (plants & animals)
    • Advantages:
      • High level of allelic variation
      • Flanks of SSR motifs-templates for specific primers to amplify the SSR alleles via PCR
      • Referred to as simple sequence length polymorphisms (SSLPs)
      • Mutation rates of SSR are about 4x10^4 – 5x10^6 /allele/generation
    • SSRs are characterized by:
      • Hypervariability
      • Reproducibility
      • Codominant nature
      • Locus specificity
      • Random dispersion throughout most genomes
      • More variable than RFLPs or RAPDs

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Quiz on genetic variation, its impact on population survival, and its role in phenotypic variation and natural selection.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser