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Dapo Adegbile Nevin Varghese Victor Veras

Dapo Adegbile Nevin Varghese Victor Veras. 1-28-10 Period 2. Summary of Polydactyly. Polydactyly is a condition in which a person has more than five fingers per hand or five toes per foot.

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Dapo Adegbile Nevin Varghese Victor Veras

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  1. DapoAdegbileNevin Varghese Victor Veras 1-28-10 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 W W h h Heterozygous Homozygous

  7. Probabiliy of Disease occuring G g • Ratio • 1GG 2Gg 1gg G g • Percentage • 25% -GG 50% - Gg 25% - gg • 75% chance of getting Polydactyly • 25% chance of not getting Polydactyly

  8. What the letters mean G g • GG – two dominant alleles • Gg – one dominant allele and one recessive allele • gg – two recessive alleles G g • Phenotype • GG = Get polydactyly • Gg = Get polydactyly • gg = normal amount of fingers • Top – Father • Bottom – Mother • Genotype • GG = Homozygous dominant • Gg = Heterozygous dominant • gg= Homozygous recessive

  9. Genotype and Phenotype possibility G g G g • 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 G G • Phenotypes • Ratio – • Percentage – G g • Genotypes • Ratio – • Percentage –

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