OMICS: Lect 15 Flashcards
1
Q
Human Genome Sequence
A
- determine entire seq of human genome.
- identify and map genes in human genome.
- find single nt polymorphisms.
- shows how few genes we have
2
Q
Annotation
A
-identifying the functions of open reading frame. Challenges: miss aspects of genome -very small ORF -small genes w/i larger genes -genes on opposing DNA strands -gene not translated into protein -other unknown RNA species
3
Q
Why is it that chrom 13, 18 and 21 are only autosomes that can be found as trisomy and compatible w/ life?
A
- because size of chrom doesn’t always correlate w/ size by gene content. (Alt splicing ->resulting in many genes, RNA editing)
- these have the smallest gene content.
4
Q
Duplications in the genome
A
- 50% of genome is repetitive sequence.
- STR (di, tri or tetra) and VNTR (slightly longer repeats); highly polymorphic regions.
- Transposons (LINES and SINES “Alu element) -> most repetitive DNA in genome.
- Pseudogenes: vestigial, duplicated and processed pseudogenes.
5
Q
Pseudogenes
A
- Vestigial: now dormant. Ex: humans have the Vit C gene but it doesn’t function.
- Duplicated genes: not expressed. Ex: one of the globin genes in the B globin locus is not expressed.
- Processed pseudogenes: introns are removed from primary transcript by nl splicing, poly A tail added. Rev transcription and integration then yield a processed pseudogene which does not contain introns and has an A-rich tract at it’s 3’ end.
6
Q
Transposons leads to a disease by?
A
- integrating into a critical spot in a genome, disrupt a gene and cause disease.
- as repetitive sequence may lead to misalignment during meiosis and gene disruption.
7
Q
DNA fingerprinting
A
- may be used to settle paternity issues via PCR.
- use highly polymorphic single locus regions like STR or VNTR loci.
8
Q
Multiplex PCR:
A
an example of STR/VNTR PCR genotyping.
9
Q
Gene/chrom duplication or amplification occurs in a variety of ways:
A
- error in homologous recombination, retrotransposition event or duplication of an entire chrom.
- duplicated gene can evolve faster and the second copy of the gene is free from selective pressure.
- In a-thalessemia; due to repetitive struct of the a-cluster, deletions are the common disease causing mechanism for a-thal.
10
Q
Red-green color blindness?
A
explained by unequal intragenic recombination btwn a pair of X-chrom during meiosis.
11
Q
Chromosomal Microarray Analysis:
A
- can detect birth abnormalities.
- allows overview of the genome.
- > 1000s of probes immobilized on a solid support.
-CGH and SNP
12
Q
CGH
A
- comparing one genome to another.
- gives copy number variation
- important in pediatrics and diagnosis of developmental abnormalities.
- can detect smaller del or insertions than G-banding.
- diagnostic tool
13
Q
SNP chip
A
- single nucleotide polymorphisms
- may inform haplotype and pharmacogenomics.
- data collection tool
14
Q
Haplotype
A
- combination of alleles at different chromosomal loci that are transmitted together.
- HapMap describes common patterns of human genetic variation.
15
Q
Genome wide assoc. studies
A
- an attempt to uncover genetic determinants of multifactorial diseases (environmental and more than one genetic component)
- created by scanning 1000s of SNP
- search for genetic variations assoc w/ a particular disease.
- > finding genetic variations that contribute to common, complex disease such as autism, asthma, cancer, diabetes type I/II, heart disease and mental illnesses.
