Genomes and Chromosomes Flashcards
week 1
What is a genome?
Total genetic content contained in a haploid set of chromosomes
What is a Transcriptome?
transcripts of DNA including alternatively spliced ones and structural RNA
result of transcription
Describe the bases found in Gene-dense vs Gene-poor human genomes.
Gene rich = Urban centers = rich in Guanine and cytosine
Gene poor = Deserts = rich in Adenine and Thymine
Approximately, how many DNA bases are exactly the same in ALL people?
99.9%
How much of the genome carries out a biochemical role?
Around 80%
How much of the Human Genome does Repetitive Sequences roughly make up?
50%
What are the five main types of genes/ sequences in the human genome?
Repetitive sequences, pseudogenes, simple sequence repeats, introns of other genes, Significant person-person structural variation.
What are Repetitive sequences?
Transposable elements, repeats and duplications
wWhat are the three regions of significant person-person structural variations.
Duplicated regions, Deleted regions and Rearranged regions
What percent of the total genome sequence does protein coding regions make up?
around 1%
What are the two parts that make up Transposons of rge Human Genome?
LINEs= Long interspersed elements
SINEs= short interspersed elements
What is Mitochondrial Eve?
Maternal ancestry – traced via mitochondrial DNA variation
Demonstrates all Europeans today descended from 7 women living in various parts of Europe 45,000 – 10 000 years ago.
What is Y Chromosome ‘ADAM’?
Paternal ancestry traced via the Y chromosome
Demonstrated: Minimal variation in sequence between populations
What did the human genome project expect to find? What instead was discovered?
Expected to find: correlation between number of protein coding genes and organism’s complexity
What was found: number of unique mRNA transcripts were relatively constant BUT number of NON-CODING RNAs dramatically INCREASE with developmental complexity.
Haplogroup
group of genetic markers that are inherited together and can be used to trace ancestary and migration.
What is the impact of Inherited Disease?
ALTERS or ELIMINATES normal gene, protein, cellular tissues and body function and affects genome and proteome
What is the impact of Bacterial Infection and how?
Alters tissue function
- produced proteins that interfere with cellular functions
-alters gene expression
- can insert genes
affects both genome and proteome
What is the impact of a Viral Infection?
Forces host genome to make viral proteins
-some interfere with normal cell functions
-some lead to production of more virus
What is the only phase in which Chromosomes appear?
M phase (mitosis)
What are Sex Chromosome Aneuplodies and two examples?
carriage of an atypical number of X and/or Y-chromosomes beyond the typical female (XX) or male (XY) complement.
Turners
XXY (Klinefelter)
What is non-invasive prenatal testing and what can it test for?
takes a blood sample from mother that contains cell-free fetal DNA
Tests for:
sex
Sex Chromosome Aneuploidies (SCA): Monosomy X (Turner) and XXY (Klinefelter syndrome)
Genetic disorders: Trisomy 21, 18 or 13
22q11.2 microdeletion
what are four prefixes associated with chromosome terminology?
Acro – tip
Sub – imperfect/below
Meta – mid
Telo - at the end/ final
What is the order of naming a chromsome? (e.g Xp11.2)
Chromosome (x), Arm (p), Region (1), Band (1) and sub-band (.2)
What is a Telomere?
region of short repetitive DNA sequences at END of chromsome.
What are the two types of chromatin? What are their characteristics?
Euchromatin
-more relaxed
-active genes
-replicates in early S-phase
-lightly stained when undergoes G-banding
Heterochromatin
-more condensed
- silent genes
- replicates late S-phase
- darkly stained when undergoes G-banding
What are the two sub-types of heterochromatin and their characteristics?
Constitutive - condensed in all cell types
Facultative - condensed in some cell types
