11III. Simple Dominant Heredity Huntington’s DiseaseLethal and caused by dominant alleleBreak down of parts of brainHow does this get passed if lethal?
12IV. Complex Patterns of Inheritance A. Incomplete DominancePhenotype of heterozygous organisms are “between” parents’ traitsRed flower (RR) with white flower (R’R’) = Pink (RR’)R produces red pigment, R’ produces no pigment
13IV. Complex Patterns of Inheritance B. CodominancePhenotypes of both parents to be produced in heterozygous individuals (expressed equally)B and W (two different uppercase letters to express alleles)
14Codominance in Humans Sickle-cell Anemia African decent and countries around Mediterranean SeaHomozygous – red blood cells shaped like half moonHeterozygous- normal and sickle shapes
15IV. Complex Patterns of Inheritance C. Sex DeterminationHumans = 46 chromosomes (23 pairs)22 pairs = AutosomesSex chromosomes – male or female (XY, XX)Abnormal numbers of sex chromosomesXO, XXX or XXY, XYY
16IV. Complex Patterns of Inheritance Sex Chromosome AbnormalitiesGenotypeGenderSyndromePhysical TraitsXXY, XXYY, XXXYmaleKlinefelter syndromesterility, small testicles, breast enlargementXYYXYY syndromenormal male traitsXOfemaleTurner syndromesex organs don't mature at adolescence, sterility, short statureXXXTrisomy Xtall stature, learning disabilities, limited fertility
17IV. Complex Patterns of Inheritance D. Sex Linked InheritanceTraits controlled by genes located on sex chromosomesY has no corresponding alleleY linked only passed from male to maleFemales must have both recessive (xx)All X-linked are expressed in MalesNo corresponding X to mask trait
18IV. Complex Patterns of Inheritance D. Sex Linked InheritanceMales pass X onto daughter, Y to sonSon receives recessive allele on X chromosome = display of recessive trait (red-green color blindness, hemophilia)
19IV. Complex Patterns of Inheritance E. Multiple AllelesTraits controlled by more than two alleles (same gene)Can be formed by mutationsEx. Blood Types
20Blood Type Blood types – A,B,AB, and O 3 Alleles – IA,IB, and i Child = AB, Mother = A, father could not be O
21Blood Type Universal Donor – O; can give blood to any individual Universal receiver – AB; can receive blood from any individual
22IV. Complex Patterns of Inheritance F. Polygenic InheritanceInheritance pattern of trait controlled by two or more genesPlant height – A,B, and C (3 genes on 3 chromosomes)Ex in humans – eye color, skin colorHow is this different than multiple allele?
23V. Environmental Influences Internal factors can influence expressionHormones, ageExternal factors can influence expressionTemperature, nutrition, light, chemicalsArctic foxes – temperature affects coat color
24V. Environmental Influences Identical twins –Same DNAMay look different because of environmentNutritionExerciseAccidents (scars, etc)
25VI. Chromosome #’s Karyotype – chart of chromosome pairs Down syndrome: chromosome 21 TrisomyHigher chance with older mothers