Lecture 1 Flashcards
1
Q
Ploidy Range
A
The number of sets in an organism while applying the formula: Ploidy level (Haploid Number) +/- 11
2
Q
Haploid Range
A
23 +/- 11 = 12-34
3
Q
Diploid Range
A
46 +/- 11 = 35-57
4
Q
Triploid Range
A
69 +/- 11 = 58-80
5
Q
Tetraploid Range
A
90 +/- 11 = 81-103
6
Q
Composite Karyotype
A
All the collected abnormalities put together. Because if every sample cell has a different karyotype ( and no 2 cells share the same structural or numerical aberrations), it can be seen which abnormalities have actionable treatments.
7
Q
Single Cell Evolution
A
- It exists simultaneously with Clonal Evolution.
- It states that just because one evolutional clone is be treated, not all clones are.
- It is multiple pockets of clones, instead of a one cell line.
8
Q
Clonal Evolution
A
- Observed in cancer, it begins with a timestamp of a karyotype for chromosomal change.
- Observing the parent cell will let us know if the mutation is outsmarting the treatment.
- It parallels Darwinian Natural Selection.
9
Q
Ring Chromosomes
A
- Formed when 2 terminal breaks occur on the same chromosome, then the top and bottom become “sticky” and form a union.
- There is a loss of genetic material.
- Like dicentrics, are highly unstable because the break of lag anaphase.
10
Q
Isochromosomes
A
- Formed when there is a misdivision of a centromere.
- Occasionally centromere divides horizontally.
- Results in 1 daughter cell with 2 sister chromatids on each arm of a chromosome.
- One arm is a mirror image of the other.
- Trisomic for one arm / Monosomic for the other.
11
Q
What is a good example of an isochromosome?
A
Turner Syndrome
12
Q
Duplication
A
- When a portion of the chromosome is duplicated.
- Extra material results in functional trisomey.
- Duplicated material can be in the same order, or inverted and reversed.
- Can be direct or indirect.
13
Q
Paracentric Inversion
A
- When both breaks are in the same arm of a chromosome.
- Centromeres are NOT involved.
- Products are either acentric or dicentric.
- Negligible outcome for an unbalanced offspring.
14
Q
Pericentric Inversion
A
- When there is a break on the short arm and the long arm of a chromosome.
- Does not effect the phenotype of the carrier.
- Each unbalanced product has a duplication, deficiency, or is nonviable.
15
Q
Inversions
A
- Results when 2 breaks occur on the same chromosome.
- The middle segment rotates 180 degrees before DNA repair.
- There is no net loss, only changes the gene order.
16
Q
What are the two types of Inversions?
A
Pericentric - Breaks on both arms
Paracentric - Breaks on only one arm
17
Q
Deletion
A
- Results in a loss of genetic material.
- Is the most common.
- Functional monosomy.
- Can be terminal or interstitial.
18
Q
Insertions
A
- Parts of a chromosome inserted into another chromosome.
- Can be direct or inverted.
- Can be Intra or Inter.
19
Q
What are the 2 types of direct Insertions?
A
Intra - Insertion within the same chromosome
Inter - Insertion between 2 or more chromosomes
20
Q
Telomeres
A
- Prevent the chromosomes from forming a circle or rings.
- The shorter a telomere is the older the person is.
21
Q
Dicentric Chromosomes
A
- Posses 2 centromeres (and 4 arms) from 2 chromosomes.
- Unless one of the centromeres is inactivated, an abnormality in mitosis, an anaphase bridge, or lagging chromosomes can occur.
- There is a loss of acentric fragments.
22
Q
Anaphase Bridge
A
Occurs when each different centromere of a dicentric chromosome migrates to the opposite side of the spindle.
23
Q
Nonreciprocal Translocation
A
- Results from unbalanced exchange of genetic material between 2 or more chromosomes.
- There is a loss or a gain of genetic material.
- Can be very problematic and lethal.
- The cell will die the next time it divides.
- Fragments will be lost with no centromere.
24
Q
45,XY,der(7)t(7;17)(q22,q11.2),-17
A
Example of a nonreciprocal translocation.
25
Derivative
- A translocation occurred but it is unknown where the chromosome came from.
- Can be generated by more than one aberration within a single chromosome.
OR
-Can be a rearrangement involving 2 or more chromosomes.
26
46, XX, der(7)add(7)(p22)del(7)(q22;q34)
Example of a Derivative
27
Acrocentric Chromosomes
- Have very small p arms.
- Are highly polymorphic (can come in different sizes).
- Were used in early forensics as identification.
28
Robertstonian Translocations
- Chromosomal rearrangement between 5 specific acrocentric chromosomes. (13;14;15;21;22)
- They are constitutional.
- They are fragile.
29
Which are the only 2 Robertsonian Translocations that are survivable after child birth?
Trisomy 13 - Patau Syndrome
Trisomy 21 - Down's Syndrome
30
45, XX, rob(14;21)(q10;q10)
Example of Robertsonian Translocation
31
Unbalanced Translocation
Loss or gain between 2 or more chromosomes.
32
Balanced Translocation
- Two breaks in a chromosome, or between 2 or more chromosomes, with no gain or loss. (They have swapped places.)
- This can result in the wrong expressions occurring.
- The increased number of cells translocated the worse the progression of the disease. Then there would be an increase in dosage or therapy due to possible resistance.
33
46,XX,t(9,22,17)
Example of a balanced translocation.
34
Anaphase Lag
- Failure of a chromosome or chromatid to be incorporated into one of the daughter nuclei after cell division because of lagging during anaphase.
- Chromosomes that do not enter a daughter cell nucleus are lost.
35
What are the 2 different types of Mixoploidy?
Mosaicism - Derived from a single zygote
Chimerism - Derived from different zygotes
36
Mosaicism
When an individual posses 2 or more genetically different cell lines all derived from a single zygote. (Can be found in humans.)
37
Chimerism
When an individual has 2 or more genetically different cell lines originating from different zygotes. (Rare and not found in humans.)
38
Nondisjunction
- Failure of paired chromosomes to separate in anaphase of Meiosis I
- Failure of sister chromatids to disjoin at either Meiosis II or Mitosis
- Produces gametes with 22 or 24 chromosomes, which after fertilizations make a trisomic or monosmic zygote
- Produces a mosaic in Mitosis
39
What are the 2 possible causes of aneuploidy?
Nondisjunction or Anaphase Lag
40
Aneuploidy
The presence of one or more extra chromosomes or the absence of one or more chromosomes.
41
What are the 2 categories of a somatic or acquired abnormality?
Structural and Numerical
42
Constitutional Abnormality
Occurs in early embryo and post fertilization (the sperm or the egg).
43
The human genome has how many bases?
3. 2 billion bases haplotype
| 6. 4 billion diploid cells
44
Genes are made up of?
- 20,000 to 24,000 protein coding
- Make up 1.5% of the genome
- "Junk" DNA
45
1 Kb is how many bases?
1,000 bases
46
1 Mb is how many bases?
1 million bases or 1,000 Kb
47
A full diploid is how big?
1.5 terabytes of data.
48
What is the average gene size?
25-30 Kb
49
How small and how big can a gene be?
As small as a single exon (like a histone).
| As big as 79 exons (2.3 Mb) (like dystrophin).
50
What is the average exon size?
150-200 bp
51
```
What are the sizes of the following:
Intron
mRNA
5'UTR
3'UTR
Coding DNA
```
Intron - 0.5 kb to 30 kb
mRNA - 2.5 kb
5'UTR - 100 bases
3'UTR - 600 to 800 bases
Coding DNA - 1.5 to 1.8 kb (500 to 600 codons)
52
What is the size limit we can see under the microscope?
5 Megabases or 5 million bases
53
What does FisH stand for?
Fluorescent in situ hybridization
54
What are the sizes of the following:
FISH
CGH Arrays
Oligonucleotide / DNA Arrays
FISH - 100 to 400 kb probes / 70 kb homebrew
CGH Arrays - detects variations at 200 bp
DNA Arrays - 7 base sequences
