Knowt
6 - Genome Diversity
Diversity of Eukaryotic Genomes and Applications of Genome Sequencing
Page 1: Overview
Introduction to diversity in eukaryotic genomes.
Discussion on the applications of genome sequencing in various fields.
Page 2: Genome, Genes, and Alleles
Genome: Complete set of genetic information in an organism's DNA.
Includes all genes and non-coding regions.
Genes: Sequences of nucleotides coding for proteins or RNA.
Found at specific loci on chromosomes.
Alleles: Variations of a gene producing slightly different gene products.
May perform similar functions despite variations in sequence.
Page 3: Understanding Chromosomes
Chromosomes structure and function:
Hold specific genes that code for amino acids, thus proteins.
Unique due to the specific order of genes contained in each.
Locus: Specific location on a chromosome where a gene is found.
Diploid (2n) somatic cells:
Contain homologous chromosomes, one from each parent.
Homologous chromosomes share the same genes in the same order but can differ by alleles.
Page 4: Diversity of Eukaryotic Genomes
All current organisms likely derived from a universal common ancestor (LUCA).
Evolutionary tree branched since LUCA:
Variation in alleles and genomes attributed to natural selection.
Key points about variation:
Greater variation exists between species than within species.
Genetic complexity does not directly correlate with genome size.
Example task:
Compare genome sizes from NCBI Genome Database across different species (e.g., complex animals vs. plants vs. bacteria).
Page 5: Variations in Genome Size
Genome size does not correlate with organism complexity.
Larger genomes have more base pairs & potentially more functional genes.
Example data:
Humans: 6.2 Gb genome (only 1-2% codes for proteins).
Banana genomes: 1.3-1.5 Gb.
Non-coding regions & "junk" DNA:
Non-coding regions serve regulatory functions, many are repetitive.
Page 6: Single Nucleotide Polymorphisms (SNPs)
SNPs: Single nucleotide changes at a specific locus causing variation.
Often found in non-coding regions of DNA.
Less than 1% nucleotide variation among humans.
Distinctions between SNPs and mutations:
Mutations: Substitutions, deletions, insertions, translocations, etc.
SNPs: Only involve single nucleotide replacements.
Page 7: DNA Barcoding and Environmental DNA
DNA barcoding: Short DNA segment used to identify species or groups of organisms.
Typically derived from a single gene, sometimes multiple.
Uses of environmental DNA:
Analyzing samples to track organism types in environments.
Identifying pathogenic contaminants in wastewater, indicating disease outbreaks.
Assessing ecosystem health through terrestrial ecosystem samples, looking for elusive or extinct species.
Page 8: Whole Genome Sequencing
Historical context of genome sequencing since the 1990s.
Mapping genomes from unicellular prokaryotes to complex multicellular eukaryotes.
Early genome sequencing efforts:
Costly and time-intensive, improved with technological advancements.
Current trends:
Accessibility and affordability of genomic sequencing for the general public.
New possibilities in medical research regarding genetic health and ancestry.
