Genome Sturcture and Annotation Flashcards
(19 cards)
How is the genome structured in eukaryotic cells?
Highly strucutred and arganised inside the cell nucleus
How is the human genome organised?
23 Chromosomes
What is a karyotype?
Chromosome complement of a cell organism, arramged as metaphase chromosomes
What is Giemsa staining used for?
Binds A:T-rich regions, marking inactive areas with few genes called G bands
What does FISH stand for?
Fluorescent in Situ Hybridization
What is FISH used for in karyotyping?
Chromosome painting using coloured fluorophores
Identifies chromosome-specific probes
Used in karyotype analysis for normal and diseased cells
Helps stuudy evolution
How is recombinant frequency calculated?
Recombinant frequency = (% of recombinant progeny / % total porgeny) x 100
How can a genetic map be constructed?
By crossing individuals with different phenotypic markers to approximate distacnes between genes
Why can’t genetic mapping be done through crosses in humans?
Ethical limitations prevent controlled breeding experiments
What type of genetic markers can be used?
Phenotypic markers (hair/eye colour)
Disease genes (colourblindness)
Mendelian inheritance traits
What are exampes of physical markers?
SNPs (Single Nucleotide Polymorphisms)
RFLPs (Restriction Fragment Length Polymorphisms)
VNTRs (Variable Number Tandem Repeats)
What is a key trait of SNPs in humans?
One SNP occurs every 1,330 base pairs
Each human has a unique SNP profile
How do forensic scientists use SNPs?
Companies use SNP profile for ancestry and ethnicity analysis
SNP pattersn help identify blood relatives
Used in criminal investigations to reconstruct family trees
Why isn’t genomic DNA sequence alone enough?
Only 2% of the human genome encodes for proteins
How is fenome annotation performed?
By identifying:
Protein-coding genes (Exons, ORFs)
RNA-coding genes (tRNA, rRNA)
Non-coding sequences (introns, promoters)
What are they two methods for identifying genes/ORFS?
1- Computational approach (sequence-based)
2 - Experimental approach (cDNA generation)
How does computational approach differ in prokaryotes vs eukaryotes?
Prokaryotes: Continuous ORFs, short promoter regions, no introns
Eukaryotes: Mutliple introns, longer promoter regions, alternative mRNAs
What is cDNA?
Complementary DNA (dsDNA copy of mature RNA, no introns)
How is cDNA generated via RT-PCR?
Reverse transcriptase (RT) makes DNA copy of mRNA
RNA is degraded
DNA polymerase amplifies cDNA using 5’ UTR-specific primers
