Human Genome Organization Flashcards
size of haploid human genome sequence
3 x 10^9 bp
Human genomic DNA is distributed on __________ chromosomes
46
The chromosomes are found in __________ pairs:
1) 22 \_\_\_\_\_\_\_\_\_\_ 2) 1 \_\_\_\_\_\_\_\_\_\_
23
autosomes (1-22)
pair of sex chromosomes (XX or XY)
Each chromosome is believed to consist of a __________
single, continuous DNA double helix
Human Genome
- is a record of human evolutionary history
- Reflects results of different selection pressures that have occurred over evolutionary time and shaped our genome (and shaped us)
- Genes and genomic features that have been adaptive have been retained
Genotype + environment = __________
phenotype
Random genomic variation
- is the fuel of evolution
- Random variation in a highly ordered structure = almost always deleterious consequences
- Genetic disease is the price we pay as a species to continue to have a genome that can evolve, i.e., that can adapt to new and changing environments
The human genome is __________ and continues to evolve
- ~30 new mutations occur in each individual
- Shuffling of regions at each meiosis due to __________
- Can produce __________ DNA changes as well as __________ DNA changes
dynamic
recombination
somatic
germ-line
Organization of the genome
- Gene-rich regions/chromosomes
- Gene-poor regions/chromosomes
- Stable regions: majority of genome
- Unstable, dynamic regions; many are disease-associated
- GC-rich regions (38% of genome), AT-rich regions (54% of genome)
__________ (i.e. non-random distribution) of GC-rich and AT-rich regions is basis for chromosomal banding patterns (cytogenetics, karyotype analysis)
Clustering
Clustering (i.e. non-random distribution) of GC-rich and AT-rich regions is basis for __________ (cytogenetics, karyotype analysis)
chromosomal banding patterns
Euchromatic regions
more relaxed
heterochromatic regions
more condensed; more repeat-rich
Genome sequencing effort focused on __________ region
euchromatic
__________ regions essentially unsequenced
Heterochromatic