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Questions and Answers
What is the primary result of gene duplication within a single cell?
What is the primary result of gene duplication within a single cell?
Orthologs are related genes that arise from gene duplication within the same genome.
Orthologs are related genes that arise from gene duplication within the same genome.
False
What is horizontal transfer in genetics?
What is horizontal transfer in genetics?
It is the transfer of DNA from the genome of one cell to another, often between different species.
Match the following terms with their definitions:
Match the following terms with their definitions:
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The phenomenon where two or more existing genes break and rejoin to form a hybrid gene is known as __________.
The phenomenon where two or more existing genes break and rejoin to form a hybrid gene is known as __________.
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Which process allows bacteria and archaea to acquire genes from neighboring cells?
Which process allows bacteria and archaea to acquire genes from neighboring cells?
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Horizontal gene transfer is common among eukaryotic cells of different species.
Horizontal gene transfer is common among eukaryotic cells of different species.
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What is a key feature of sexual reproduction in eukaryotes regarding genetic exchange?
What is a key feature of sexual reproduction in eukaryotes regarding genetic exchange?
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About 18% of all of the genes in the present-day genome of E. coli have been acquired by __________ from another species within the past 100 million years.
About 18% of all of the genes in the present-day genome of E. coli have been acquired by __________ from another species within the past 100 million years.
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Match the following terms with their correct descriptions:
Match the following terms with their correct descriptions:
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Study Notes
Intragenic Mutation and Gene Duplication
- Intragenic mutations involve random modifications to an existing gene's DNA sequence due to replication errors.
- Gene duplication creates a pair of identical genes within a single cell, allowing one gene to mutate and specialize over time.
- Gene families arise from repeated rounds of duplication and divergence, evident in organisms like Bacillus subtilis, which has 47% gene identity among its genes.
Types of Gene Relationships
- Orthologs are genes in two separate species that share a common ancestor.
- Paralogs are related genes formed by duplication within a single genome, likely diverging in function.
DNA Segment Shuffling and Horizontal Gene Transfer
- DNA segment shuffling creates hybrid genes by rearranging DNA segments from different genes.
- Horizontal gene transfer enables DNA movement between cells, including different species, contrasting with vertical transfer.
- Prokaryotic organisms, including bacteria and archaea, frequently engage in horizontal transfer, often mediated by viruses (bacteriophages).
Antibiotic Resistance and Gene Transfer
- Horizontal gene transfer allows for the transfer of antibiotic resistance genes, leading to the emergence of new strains, such as penicillin-resistant Neisseria gonorrhoeae.
- Approximately 18% of E. coli genes have been acquired through horizontal transfer over 100 million years.
Eukaryotic Genetic Exchange
- In eukaryotes, sexual reproduction causes genetic exchange between initially separate lineages, emphasizing species-specific gene exchange.
- These processes leave distinct traces within an organism's DNA, demonstrating the occurrence of major genetic changes over time.
Gene Function Discovery through Sequencing
- By sequencing a newly discovered gene, researchers can search databases for related genes and infer function.
- Research on the PCSK9 gene identified mutations that significantly lower LDL cholesterol levels and reduce heart disease risk.
- Pharmaceutical developments based on PCSK9 interactions have led to antibody-based drugs that can reduce LDL cholesterol by up to 70%.
Historical Insights into Genetics
- Evidence of domestication and selective breeding dates back to 8000-1000 B.C., showcasing early manipulation of genetic traits.
- Hippocratic School and Aristotle's writings from ancient Greece explored heredity, suggesting active "humors" influenced traits.
Evolution of Genetic Understanding
- The theory of epigenesis proposed by William Harvey highlighted organism development from fertilized embryos, challenging the preformation theory of miniature adults.
- The cell theory, established in the 1830s, emphasized all organisms are composed of cells derived from pre-existing cells.
DNA and RNA Structure
- DNA, discovered by Watson and Crick in 1953, has a double helix structure composed of nucleotides.
- RNA comprises ribose sugars and uracil instead of thymine, and is generally single-stranded.
Proteins and Biological Function
- Proteins, formed from 20 different amino acids, perform diverse biological functions.
- Enzymes are the largest protein category, acting as biological catalysts to lower activation energy in reactions.
- Hemoglobin serves as a critical protein in red blood cells, binding oxygen for transport.
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Description
This quiz covers intragenic mutations and gene duplication processes, explaining how existing genes can be altered or duplicated within a cell. Explore the mechanisms behind these genetic changes and their implications for gene families. Test your knowledge on these fundamental concepts in genetics.
