Genomes Flashcards
What is genomics?
- Every cell in the organism contains a complete copy of the genome.
- Genomics is the study of an organism’s complete set of genes, known as its genome, including all of its DNA sequences.
- Genomics explores (1) the organization, (2) function, (3) evolution, and (4) interactions of genes within an organism.
- It provides a comprehensive view of an organism’s genetic makeup, allowing us to understand the basis of life.
Genome
an organism’s complete set of DNA
an organism’s complete set of DNA
Genome
What does genomics explore within an organism? [4]
- Genomics explores the (1) organization, (2) function, (3) evolution, and (4) interactions of genes within an organism.
- It provides a comprehensive view of an organism’s genetic makeup, allowing us to understand the basis of life.
Advances in Genomics have revolutionized various fields (some examples are): [4]
- Medicine: Personalized medicine, genetic disease diagnosis, and drug development.
- Evolutionary Biology: Understanding species evolution and relationships.
- Biotechnology: Engineering organisms for various applications.
- Forensics: DNA profiling for crime solving.
In general, genomics helps in unraveling the complexity of life and offers insights into human health, biodiversity, cell biology.
How can genomics improve crop production?
- Crop Yield Enhancement: Identification of genes responsible for desirable traits such as high crop yield, disease resistance, and tolerance to environmental stressors.
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Precision Breeding: Selection of specific genes, breeding programs can create new crop varieties with
improved characteristics.
How does genomics contribute to food quality?
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Enhancing Taste and Texture : Genomics helps developing food products with improved taste, texture, and
sensory qualities by identifying genes associated with these attributes. -
Shelf Life Extension : Understanding the genetics of spoilage and deterioration processes can lead to the
development of foods with longer shelf lives.
How does genomics contribute to food safety?
- Pathogen Detection : Genomic analyses are used to detect and identify foodborne pathogens like Salmonella, E. coli, and Listeria in food products.
- Tracing Contamination Sources : Genomics helps trace the sources of foodborne outbreaks, enabling quick interventions and recalls.
How does genomics contribute to nutrition science?
- Personalized Diets : Genomics research helps in understanding how an individual’s genetic makeup influences their nutritional needs. Helps developing personalized diets.
- Nutrigenomics : Studying how specific nutrients interact with genes to impact health and metabolism.
How does genomics help with allergen detection?
Genomic techniques can be used to detect and identify potential allergens in food items, which is crucial for labeling and ensuring food safety for individuals with allergies.
What is the structure and variation of the nuclear genome in eukaryotes?
- DNA in different organisms is made from the same molecules.
- In eukaryotes, the nuclear genome is split into a set of linear DNA molecules, each contained into a chromosome.
- Chromosomes are always linear.
- Chromosome number varies among organism but is unrelated to the complexity (yeast=16, human 23, walnut 32, fruit flies=4).
The 30 nm chromatin fiber
the major type of chromatin in the nucleus during interphase, the period between nuclear divisions
How is it that the chromosomes are much shorter than the DNA they contain?
- The genome is packed through DNA binding proteins called Histones
Describe DNA during nuclear division.
- more compact packaging (metaphase chromosomes)
- The two copies of chromosomes are held together at the centromere (in plants 0.4-3Mb made up largely of 178-180 bp repeat sequences; in yeast is short, a single copy sequence), which has a specific position within each chromosome.
- The arms of the chromosome, which are called chromatids and have terminal structures called telomeres (made up of hundreds of copies of a repeated motif, 5ʹTTAGGG 3ʹ in humans)
Describe gene distribution.
Genes appear to be distributed at random with variations in gene densities along the chromosome
Describe the genomic regions in this 50kb segment of chromosome 12 of the human genome.
- 4 genes (discontinuous from presence of exons and introns)
- 88 genome wide repeat sequences (transposable elements) including:
- LINEs=long interspersed nuclear elements
- SINEs=short interspersed nuclear elements
- LTR=long terminal repeats
- DNA transposons
- 7 microsatellites (short motif, CA, CAAA, CCTG, CTGGGG, etc. is repeated in tandem)
5’CACACACACACACACACA 3’
3’GTGTGTGTGTGTGTGTGT 5’ - 30% of nongenic , nonrepetitive DNA, single copy DNA of no function
Describe the composition of the human genome.
In the genome exons are 48Mb, 1.5% of the total.
44% is taken by genome wide repeats.
What is genic DNA?
- “Single” copy genes
- Duplicated genes
- may occur at a single or several loci on different chromosomes
- functional multi gene families with same function (e.g. 5S ribosomal RNA in human is in 2000 copies - probably because cells need a lot of ribosomes, and so they need a lot of sources of the code for efficiency)
- functional multi gene families with slightly different function (biochemical, developmental, tissue specific)
What is a pseudogene?
Genes that are not functionally active (evolutionary relics)
- Pseudogenes are DNA sequences that resemble functional genes but have lost their ability to produce proteins or functional RNA.