dapo adegbile nevin varghese victor veras

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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. - PowerPoint PPT Presentation


  • 1-28-10Period 2

  • 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 addedUsually 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

  • The cause of the disorder is usually found on chromosome 13.However for some cases it is not knownThere is another gene or chromosome that the mutation could happen in that could cause polydactyly

  • Mode of InheritancePolydactyly 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 syndromeEx. Blooms syndromeEx. Jeunes thoracic dystrophy syndrome

  • What are Alleles? A person has two alleles per geneYou get one of the two alleles in a gene from your father and the other from your motherRecessive alleles are represented by the letter of the characteristic in lower-case formDominant alleles are represented by the letter of the characteristic in capitalR Dominantr 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 allelesThe characteristic will be recessive if the gene has two recessive genes only

  • GgG

    g w wW

    W Heterozygous Homozygous hhh





  • G gG

    g Ratio1GG 2Gg 1gg

    Percentage 25% -GG 50% - Gg 25% - gg

    75% chance of getting Polydactyly

    25% chance of not getting Polydactyly


  • G gG

    gGG two dominant allelesGg one dominant allele and one recessive allelegg two recessive alleles PhenotypeGG = Recieve polydactylyGg = Receive polydactylygg = Normal amount of fingers GenotypeGG = Homozygous dominantGg = Heterozygous dominantgg = Homozygous recessiveTop FatherLeft Mother


  • G gG

    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


  • G gG

    gGenotypeRatio 1 GG; 2 Gg; 1ggPercentage 75% chance receive disease25% chance of not getting disease

    PhenotypeRatio 3 with Polydactyly; 1 without PolydactylyPercentage 75% of getting Polydactyly


  • Female circleMale Square

    All green homozygous recessive gene, person doesnt have the disease, person has 2 healthy alleles

    Half green, half black (or star) heterozygous gene, person has the disease because you only one dominant gene with the disease to get it

    All black homozygous dominant. Has the disease.

  • Student PracticeKey circle female square male shaded in (black) two dominant alleles not shaded (red) two recessive alleles half shaded one dominant and one recessive allele

  • If two parents are homozygous dominant, how likely would it be for a child not have the disease?

    If one parent is homozygous dominant but another is homozygous recessive, is it possible for one of the children not to obtain the disease?

    If one parent were heterozygous dominant and homozygous recessive, how likely is it for a child to get the disease?

    Questions????????0% child would wind up homozygous dominant

    Each of the children will wind up heterozygous dominant