1. Dapo Adegbile Nevin Varghese Victor Veras
Period 2

2. Summary of Polydactyly
Polydactyly is a condition in which a person has more than five fingers per hand or five toes per foot.
Polydactyly occurs in the womb; instead of developing only one thumb and four fingers an extra finger is added
Usually the hand is formed in the womb and when it is being split it is made into 4 fingers, 1 thumb. However sometimes an extra split occurs and abnormal number of fingers is produced
It is a autosomal dominate characteristic

3. Chromosome Disorder is Located on
The cause of the disorder is usually found on chromosome 13.
However for some cases it is not known
There is another gene or chromosome that the mutation could happen in that could cause polydactyly

4. Mode of Inheritance Polydactyly is autosomal dominant.
Autosomal dominant means that an offspring can get this disease by having it passed down from just one parent.
Polydactyly occurs because of genetic disorders or errors in fetal development.
Polydactyly can also be a symptom for another disease.
Ex. – Bardet-Biedl syndrome
Ex. – Bloom’s syndrome
Ex. – Jeune’s thoracic dystrophy syndrome

5. What are Alleles? A person has two alleles per gene
You get one of the two alleles in a gene from your father and the other from your mother
Recessive alleles are represented by the letter of the characteristic in lower-case form
Dominant alleles are represented by the letter of the characteristic in capital
R – Dominant
r – Recessive
The dominant alleles and the recessive alleles both represent two different possible characteristics.
The “characteristic” will be dominant if the gene has one dominant allele or two dominant alleles
The “characteristic” will be recessive if the gene has two recessive genes only

6. Punnent Square – Demonstration
G g
w w
h h G g GG Gr gg Ww hh W h
Heterozygous
Homozygous

7. Probabiliy of Disease occuring
G g
Ratio
1GG Gg gg G g GG Gg gg
Percentage
25% -GG % - Gg % - gg
75% chance of getting Polydactyly
25% chance of not getting Polydactyly

8. What the letters mean GG – two dominant alleles
Gg – one dominant allele and one recessive allele
gg – two recessive alleles G g GG Gg gg
Phenotype
GG = Recieve polydactyly
Gg = Receive polydactyly
gg = Normal amount of fingers
Top – Father
Left – Mother
Genotype
GG = Homozygous dominant
Gg = Heterozygous dominant
gg = Homozygous recessive

9. Genotype and Phenotype possibility
G g G g GG Gg gg
Phenotype
- Ratios- 3 for polydactyly : 1 for normal
- Percentage – 75% chance of polydactyly
25% chance of normal # of f fingers
Genotype
- Ratios- 1 GG : 2 Gg : 1 gg
- Percentages- 25% GG : 50% Gg : 25%gg

10. Student Practice Phenotypes Genotypes G G G Ratio – Percentage – g

11. 3 Generation Hypothetical Pedigree – Autosomal Dominant
Female – circle
Male – Square
All green – homozygous recessive gene, person doesn’t have the disease, person has 2 healthy alleles
Half green, half black – heterozygous gene, person has the disease because you only one dominant gene with the disease to get it

12. Student Practice Key – circle – female square – male
shaded in – two dominant alleles
not shaded – two recessive alleles
half shaded – one dominant and one recessive allele