lecture 6 Flashcards
The function of meiosis
1- type of cell division that reduces the number of chromosomes by half. Essential for producing sperm and egg.
Genetic linkage
the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.
what is a haplotype
linked genes
how does genetic linkage helps scientists in research areas?
If a gene causing a disease is linked to a known genetic marker, researchers can use that marker to locate the disease gene.
- Helps to detect genetic locations
-helps scientists study how genetic material is passed down in generations.
DNA polymorphisim?
natural variations or differences in DNA sequence.
Single nucleotide polymorphisim
The most common type of DNA polymorphism which involves a mutation in a single nucleotide.
The human genome project
It is a research that helped a lot to know which and where DNA varies. It is a template/reference to compare now.
1-It took 13 years to complete
2-researchers from 20 different universities attended.
Steps taken in the human genome project:
1-identify all human genes
2- Determine the sequence of all DNA
3- store the info in databases for future research.
How do we measure SNPs?
1-There are chips to detect SNP. These chips measure around 600 000 +bases.
2- Bases incuding SNPs close to each other are inherited together since they are linked. Means we actually capture 15 000 000 of the variation.
GWAS
A study that asseses the association between individual differences in a quantiative character and DNA variation throughout the genome.
Reasons to investigate genetic effects
1- An identified gene can become a candidate and reveal the mechanism behind it.
2- the gene can be possible target for therapy, educational improvement etc.
3- we can measure the SNP and predict people’ s traits.
Polygenic score
A measure of genetic predisposition for complex traits and disease risk.
1-Identifies groups as having high or low genetic risk.
2-It has a normal distribution.
Study of the association between polygenic prediction and educational attaintment
1-Thousands of SNPs weakly associated with educational attaintment.
2- It could partially predict how far someone would go in school but genetics is only one factor.
Problems with GWAS
1-Europe centric, most participants are white Europeans
2-Different genetic populations have different blocks.
3-GWAS and PGS will be inflated. Half of the effects comes from the environment no pure additive gentic effect.
