Complex patterns of inheritance Chapter 13

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Complex patterns of inheritance Chapter 13. Pedigrees. Tracking Family History. Pedigrees. A chart that shows multiple family generations and relationships to track the inheritance of genetic traits. Pedigrees. Can be used to determine genotypes of family members . - PowerPoint PPT Presentation


  • Tracking Family History

  • A chart that shows multiple family generations and relationships to track the inheritance of genetic traits.

  • Can be used to determine genotypes of family members.Can be used to help predict probability of future generations expressing certain traits.Important tool for genetic counselors

  • Pedigree 1: An idealized pedigree of a family with hypercholesterolemia, an autosomal dominant disease where the heterozygote has a reduced number of functional low density lipoprotein receptors.

  • Incomplete dominance dominant & recessive traits are blendedExample: Four oclock flower color red, white, pinkRemember: Vegetable juice

  • Codominance dominant & recessive traits both show up completely and individuallyExample: Blood types A & B, Horse coat colorRemember: Salad & cows

  • Multiple alleles - More than 2 alleles control the phenotypeExample: blood types A, B, O, eye color

  • Polygenic traits more than one gene controls phenotypeExamples: skin (4 genes), fingerprints

  • Epistasis = one gene can interfere with the expression of anotherExamples: mouse fur color (5 genes) one gene overshadows the othersAlbanism no pigment

  • The environment can influence gene expressionAffects phenotype

    Examples:Sun exposure affect s skin & hair colorTemperature sea turtles produce more females in warm years and more males in cold yearsIdentical twins nutrition, healthcare & physical activity influence appearance

  • An individuals fingerprints are controlled by polygenic inheritance, but also by the fetal environment. The ridge pattern of a fingerprint can be altered during weeks 6 13 of fetal development as the fetus touches the wall of the amniotic sac with its fingertips.

    Identical twins who have identical genes have different fingerprints.

  • There are three alleles to bloodAi (antigen for A)Bi (antigen for B)Oi (antigen that can be changed called H)Ai produces the antigen A found on the RBC and co dominateBi, antigen B, co dominateOi, recessive changing antigen

  • Blood TypeAntigenAntibodiesReceives FromDonates ToAA, HAnti-BA, OA, ABBB, HAnti AB, OB, ABABA, B, HnoneA, B, AB, OABOHAnti-AAnti - BOA, B, AB, O

  • During mitosis, the 23 pairs of human chromosomes condense and are visible with a light microscope. A karyotype analysis usually involves blocking cells in mitosis and staining the condensed chromosomes with Giemsa dye, G. The dye stains regions of chromosomes that are rich in the base pairs Adenine (A) and Thymine (T) producing a dark band.These bands are not a single gene but represent hundreds of genes.

  • analysis involves comparing chromosomes length the placement of centromeres the location and sizes of G-bands (stains)



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