Ch 12 Inheritance, Genes, and Chromosomes

  1. Mendell did what?
    • created theory of inheritance
    • used pea plants, controlled pollination
  2. Heritable Trait
    A trait passed from parent to offspring
  3. True Breeding traits
    observed trait that is the only one present throughout many generations
  4. Ressesive traits (lower case letter)
    trait that dissapears for a generation then reappears
  5. Dominant Trait (capital letter)
    Appears in the next generations
  6. reciprocal crosses
    proves that each parent contributes genetic material equally
  7. Particulate Thoery
    • Each plant has 2 genes for each character
    • heritible units are discrete particles
  8. Genome
    All genes in an organism
  9. Alleles
    different forms of a gene
  10. Homozygous
    individuals with 2 copies of the same allele
  11. Heterozygous
    individuals with 2 different alleles
  12. phenotype
    • physical apearance of an organism
    • EX-spherical seeds, wrinkled seeds
  13. Genotype
    • the genetic make up
    • EX-SS, Ss, ss
  14. The Law of Segregation
    • two copies of a geene seperate in reproduction
    • EX- an Ss parent gives on S to one offspring and the s to the other
  15. Punnett Squares
    • Image Upload 2
    • helps predict allele combinations
  16. Locus
    • a site on a chromosome where the gene resides
    • it encodes a particular character
  17. Test Crosses
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    • helps detirmine whether an individual is homozygous or heterozygous
    • process-crossing an unknown individual with a homozygous recessive
  18. dihybrid cross
    • crossing SsYy and SsYy
    • Has 2 genes and are identical
  19. The law of independen assortment
    • alleles of different genes assort independently during gamete formation
    • *only applies to genes on different chromosomes*
  20. Probability
    • If the event is certain probability=1
    • If the event cannot happen probability=0
    • All other events in between have probability between 0 and 1
  21. pedigrees
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  22. Mutation
    rare, stable, inherited changes in the genetic material
  23. Wild type
    allele present in most of population
  24. Polymorphic
    locus with wild-type alleles present < 99% of the time
  25. incomplete dominance
    alleles that are neither dominant or recessiveImage Upload 12
  26. Codominance
    2 alleles at one locus producing phenotypes that are both present in the heterozygote
  27. Pleiotropic
    a single allele that can have multiple phenotypic effects
  28. Epistasis
    phenotypic expression of one gene being influenced by another
  29. Inbreeding
    mating among close relatives
  30. heterosis
    a cross between 2 different true breeding homozygotes resulting in stronger, larger phenotypes
  31. penetrance
    proportion of individuals with a certain genotype that show the phenotype
  32. expressivity
    degree in which genotype is expressed in an individual
  33. Quantitative trait loci
    genes taht determine complex characters
  34. linkage group
    formed by all of the loci in a chromosome group
  35. absolute linkage (rare)
    genes at different loci on the same chromosome sometimes seperate
  36. recombinant frequencies
    where recombinant offspring appear
  37. genetic maps
    • can be made using recombinant frequencies
    • shows the arrangement of genes along a chromosome
  38. distance between genes
    Map unit (unit=centimorgan, cM)
  39. monoecious
    • "one house"
    • both male and female prodused from one
  40. dioecious
    • "two houses"
    • male and female produced by seperate individuals
  41. sex chromosome
    • determines sex of an individual
    • EX- XY, XX
  42. Autosomes
    both sexes having 2 copies of all other chromosomes
  43. nondisjunction in sex chromosomes
    • sister chromosomes fail to seperate in meiosis
    • resullts in an abnormal amount of chromosomes
  44. Possible outcomes for nondisjunction in sex chromosomes
    • X-turners syndrome
    • XXY-klinefelter syndrome
  45. Primary sex determination
    • Y chromosome encoded protien
    • if present=male offspring
    • not present=female offspring
  46. secondary sex determination
    • results in outward characteristics of each sex (not detirmined directly by Y chromosome)
    • determined by genese on autosomes and X chromosomes controlling hormones
  47. hemizygous
    • males only have 1 copy
    • -y chromosomes carry few genes
    • -x chromosomes carry many genes
  48. sex-linked inheritance
    a character is governed by loci on the sex chromosomes
  49. sex pilus
    a projection that initiates contact between bacteria
  50. conjugation tube
    cytoplasmic bridge that forms between cells
  51. plasmids
    small circular chromosomes found in bacteria
Card Set
Ch 12 Inheritance, Genes, and Chromosomes
Bio. Lecture Ch 12