Human genetics

• human genome protogen


  aims to sequence the whole genes of humans.
• proband


  individual with affected case, point of interest
• propositus


  male proband
• proposita


  female proband
• Autosomal dominance


  o Only requires one dominant allele for expression

  o Usually observed every generation
• Autosomal recessive


  o Requires both alleles to be recessive

  o For carriers, it skips generations.
• Sex-influenced


  Although the penetrance per generation is the same, the expressivity is different.
• Sex-linked dominance


  Pedigree shows affected males with unaffected wives transmit traits to daughters only
• sex-linked recessive


  Pedigree shows affected females with unaffected husbands transmit the trait to sons only, although the daughters are carriers of the gene.
• sex-linked recessive


  colorblinded
• Sex-linked Dominance


  reduced enamel of the teeth
• autosomal recessive


  tongue folding
• sex-influenced


  The gene exhibit greater penetrance in one sex.
• sex-influenced


  baldness
• Group A


  chromosome 1 , 2 , 3
• Size Large

  Group A & B

  Size Large
• Group B


  Chromosome 4,5
• Group C


  6-12, X
• Group D


  13, 14, 15
• Group E


  16, 17, 18
• Group F


  19, 20
• Group G


  21, 22 & Y
• Group C & D

  Size Medium
• Group E & F


  Size Short
• Group G


  Very short
• Group A & E


  Metacentric
• Group B, C & F


  Submetacentric
• Group D & G

  Acrocentric
• Metacentric


  centromere within the center of sister chromatids
• Submetacentric


  centromere a somewhat off center
• Acrocentric


  located near the end of the chromosome
• Polyploid


  has not been observed in humans, it is lethal.
• Triploidy


  17% of spontaneous abortion and 3% of still birth and new born deaths are due to
• Aneuploidy


  has been observed in humans, and may be classified into autosomal aneuploid and sex chromosome aneuploid
• Aneuploidy


  Leads to aberrations in the phenotype and growth and development of humans
• Down Syndrome


  Trisomy 21/22
• Down Syndrome


  Possible mental and motor developmental retardation
• Down Syndrome


  1 in 665 live birth and is correlated to mother's age
• Down Syndrome


  Slanting narrow eyes, saddle nose, large ridged tongue, flattened face, broad and short skull
• Edward Syndrome


  trisomy 16/17/18