Download My Genetic Profile Worksheet

My Genetic Profile Worksheet
Human genetic characteristics and phenotypes
Characteristic
Dominant Phenotype
Dimples
Present (D)
Hairline
Widow’s peak (W)
Tongue rolling
Roller (R)
Thumb placement with folded
Left thumb on top (P)
hands
Recessive Phenotype
Absent (d)
Straight (w)
Non-roller (r)
Right thumb on top (p)
Parent #1
Phenotype
Genotype
Dimpled
Dd
Straight
ww
hairline
Tongue roller
Rr
Left thumb on
PP
top
Parent #2
Phenotype
Genotype
Dimpled
Dd
Widow’s peak
Ww
Non- roller
Right thumb
on top
rr
pp
Child (F1)
Phenotype
Genotype
Grandchild (F2)
Phenotype
Genotype
Pedigree Chart for a SINGLE characteristic
Parent #4
_____
Parent #3
_____
Parent #2
_____
Parent #1
____
Child #2
_____
Child #1
_____
Grandchild
_____
STAO 2011 – The Promise and Pitfalls of Genetics (SBI3U)
Session #1019
www.facebook.com/nelsonschoolsciencek12
Presenter: Doug Fraser
What are the chances?
In this investigation you will model a cross between two heterozygous individuals. You will then
determine the genotype and phenotype ratios of your model F1 generation. In addition, you will
investigate the role that sample size and probability play in producing a 25:50:25 ratio in the F1
generation.
Equipment and Materials: two small opaque bags containing 40 beads each (20 blue beads and 20 red
beads)
Note: Red beads are the dominant allele, R, for red flowered, and the blue beads are the recessive allele,
r, for blue flowered. Together, the two pouches represent the parents of the P1 generation.
Without looking, draw one bead from bag 1 (P1) and one bead from bag 2 (P2).
This represents the joining of two gametes to form a new individual. Record the “genotype” of this
offspring. Return the “gametes” to their original bags. Repeat for a total of 20 times.
Offspring Genotypes
1
2
11
12
3
4
5
6
7
8
9
10
13
14
15
16
17
18
19
20
Expected Genotype ratio:
______ RR : ______ Rr: ______ rr
Expected Phenotype ratio:
______ Red : ______ Blue
Actual Genotype ratio:
______ RR : ______ Rr: ______ rr
Actual Phenotype ratio:
______ Red : ______ Blue
How did your results compare to the expected ratio?
How did the total class results compare to the expected ratio?
STAO 2011 – The Promise and Pitfalls of Genetics (SBI3U)
Session #1019
www.facebook.com/nelsonschoolsciencek12
Presenter: Doug Fraser
A Velcro Model for Microarrays
A Velcro analogy model (VAM) can be used to effectively introduce and model the principles of
microarray technology.
Prior to conducting the activity the teacher introduces the basic theory/concepts behind the use of
microarray technology as follows:
DNA/RNA basics
• When a gene is active in a cell the DNA sequence of the gene is transcribed into an mRNA
molecule.
• The mRNA delivers this genetic instruction into the cytoplasm where it is used to make a protein
or part of a protein (a polypeptide)
• RNA is very similar to DNA in that for every base in the DNA gene sequence, the cell assembles a
matching RNA base.
• Therefore the mRNA molecule will have a set of bases that are complimentary to the original
DNA strand.
• NOTE: Geneticists are able to use mRNA from a cell to make a complimentary copy of DNA
(cDNA) that will match up with original DNA in the gene.
Original DNA strand
G C A T G G A A T C C...
Complimentary DNA
C G T A C C T T A G G...
(made using mRNA)
Microarray basics
• Microarrays contain hundreds or thousands of clusters of single-stranded DNA molecules
attached to specific locations on a glass slide
• Each cluster consists of identical copies of DNA that corresponds to a specific gene. So one
microarray will have clusters of DNA corresponding to 100’s or 1000’s of different genes.
o Note that these are not “entire” genes but large fragments of the coding portions of the
genes – enough to be unique to each gene.
• Each DNA cluster will be strongly attracted to any cDNA made from complimentary mRNA
strands. For example: DNA strands with the base sequence TTCAGGCAG will be attracted to any
cDNA strands with the sequence AAGTCCGTC. In other words each DNA cluster will be attracted
to cDNA that were made using mRNA sequences that were transcribed from the same gene.
• The microarray is exposed to cDNA made using ALL the mRNA being produced by a particular
group of cells. The different cDNAs will become “stuck” to their matching DNA clusters.
• One can then determine which genes were active in the cells simply by observing which clusters
of DNA have cDNAs attached to them!
• By comparing the microarray results for different cells you can compare gene activity in each
cell!
STAO 2011 – The Promise and Pitfalls of Genetics (SBI3U)
Session #1019
www.facebook.com/nelsonschoolsciencek12
Presenter: Doug Fraser
Liver tumor tissue
Normal liver tissue
Diseased pancreas cells
Gene
Membrane protein #1
Respiration protein #1
Unknown #1
Unknown #2
Membrane protein #2
Milk protein
Ribosomal protein
Unknown #3
Insulin
Respiration protein #2
Hemoglobin
Glucagon
Normal pancreas cells
Microarray Observations and Analysis:
Questions:
1) Compare the activity of genes in normal pancreas cells with those of diseased pancreas cells. What
might this suggest about the possible cause of the disease and effect that this disease may have on
the cells normal activity?
2) Compare the activity of genes in normal liver tissues with those of liver tumor tissue. What might
this suggest about the possible cause of the cancer and effect that this may have on the tissues
normal activity?
3) Compare the activity of genes in normal pancreas and normal liver cells. Why aren’t the same genes
active in all healthy human cells?
4) Which genes were active in all cells? What might this suggest about the roles and importance of
these genes?
5) Which genes were not active in any of the cells? Where in the body would you expect to find these
genes active?
STAO 2011 – The Promise and Pitfalls of Genetics (SBI3U)
Session #1019
www.facebook.com/nelsonschoolsciencek12
Presenter: Doug Fraser
The VAM Microarray:
Each pair should have the identical microarray Velcro (hooks) board and two envelopes with sets of
cDNA strands (Velcro loops) – each envelope representing the cDNA from a given tissue/cell sample.
Make board out of “foam core” board and use adhesive-backed Velcro.
Microarray Board Layout:
Membrane protein #1
(long)
AATCGGCGATCT
Unknown #2
(medium)
TTGCGGAAT
Ribosomal protein
(long)
CGGATTATCCGG
Respiration protein #2
(medium)
ACTGTTACC
•
•
•
Respiration protein 1
(medium)
CGCCTTATT
Membrane protein #2
(short)
TATAGG
Unknown #3
(short)
CGTAAA
Hemoglobin
(long)
AATGAGGGAATT
Unknown #1
(medium)
CCCTAGGAG
Milk protein
(long)
GATCCGGACCGT
Insulin
(short)
CGTAAT
Glucagon
(short)
TACACC
Make DNA (Velcro) strips in three different lengths
Write base codes and protein identification above DNA Velcro strips that are on the board
Attach labels with base codes on the back of each separate sample DNA strip to be placed in
envelopes
So for each “board” you will need four long, four medium, and four short pieces of Velcro.
Plus labels that include the gene “name” and the base sequence
The following is assuming you will have 8 microarray “boards” and one group at each board – with
two envelopes per board as follows:
Groups 1,2,3 - Normal Pancreas and Diseased Pancreas cells
Group 4,5,6 – Normal Liver tissue and Liver Tumor tissue
Groups 7,8 – Normal Pancreas and Normal Liver tissue cells.
Envelope contents:
Normal pancreas cells:Mem1, resp1, unknown 1, mem2, ribo, insulin, resp2, glucagon
Diseased pancreas cells:Mem1, resp1, mem2, ribo, resp2, glucagon
Normal liver tissue: Mem1, resp1, unknown 2, ribo, resp2
Liver tumor tissue: Mem1, resp1, unknown 2, ribo, unknown 3, resp2
Compliment codes for cDNA velcro in envelopes
Membrane protein 1
AATCGGCGATCT
TTAGCCGCTAGA
Unknown #2
TTGCGGAAT
AACGCCTTA
Ribosome protein
CGGATTATCCGG
GCCTAATAGGCC
Respiration protein #2
ACTGTTACC
TGACAATGG
Respiration protein 1
CGCCTTATT
GCGGAATAA
Membrane protein #2
TATAGG
ATATCC
Unknown #3
CGTAAA
GCATTT
Hemoglobin
AATGAGGGAATT
Not needed
Unknown #1
CCCTAGGAG
GGGATCCTC
Milk protein
GATCCGGACCGT
Not needed
Insulin
CGTAAT
GCATTA
Glucagon
TACACC
ATGTGG
STAO 2011 – The Promise and Pitfalls of Genetics (SBI3U)
Session #1019
www.facebook.com/nelsonschoolsciencek12
Presenter: Doug Fraser