Chapter 9

  1. genetics
    the science of heredity
  2. character
    a heritable feature that varies among individuals in a population. such as flower color in pea plants
  3. trait
    a variant of a character. such as purple or white flowes
  4. self-fertilize
    the fusion of sperm and egg produced by the same individual organism
  5. cross fertilization
    the fusion of sperm and egg derived from two different individuals
  6. true breeding
    self fertilization produced offspring all identical to the parent
  7. hybrids
    the offspring of parents of two different species or of two different varieties of one species; the offspring of two parents that differ in one or more inherited traits; an individual that is heterozygous for one or more pairs of genes
  8. cross
    a mating of two sexually reproducing individuals, often used to describe a genetics experiment involving controlled mating
  9. P generation
    the true-breeding parental plants.(P for parental)
  10. F1 generation
    the hybrid offspring of the P generation. (F for filial, "son")
  11. F2 generation
    when F1 plants self-fertilize or fertilize each other
  12. monohybrid cross
    the parental plants differ in only one character
  13. alleles
    an alternative version of a gene
  14. homozygous
    an organism that has two identical alleles for a gene
  15. heterozygous
    an organism that has two different alleles for a gene
  16. dominant allele
    the allele that determines the organisms appearance
  17. recessive allele
    the allele that has no noticeable effect on the organisms appearance
  18. law of segregation
    rule in inheritance that individuals have two alleles for each gene and that when gametes form by meiosis, the two alleles separate, each gamete resulting with only one allele of each gene;also known as first law of inheritance
  19. Punnett square
    shows the four possible combinations of gametes; shows the results of random fertilization
  20. genotype
    an organisms genetic makeup
  21. phenotype
    an organisms expressed, or physical, traits
  22. dihybrid cross
    an experimental mating of individuals at two genetic loci
  23. law of independent assortment
    each pair of alleles segregates independently of other pairs of alleles during gamete formation
  24. rule of multiplication
    states that the probability of a compound event is the product of separate probabilities of the independent events
  25. rule of addition
    states that the probability that an event can occur in two or more alternative ways is the sum of the separate probabilities of the different ways
  26. pedigree
    a family tree representing the occurrence of heritable traits in parents and offspring across a number of generations
  27. carriers
    an individual who is heterozygous to a recessively inherited disorder and therefore does not show symptoms of the disorder but who may pass on the recessive allele to offspring
  28. cystic fibrosis
    a fatal genetic disease in the U.S. a person who has two copies of the allele has cystic fibrosis, which is characterized by an excessive secretion of very thick mucus from the lungs, pancreas, and other organs
  29. inbreeding
    a mating of close relatives that is more likely to produce offspring homozygous for recessive traits
  30. achondroplasia
    a dominant disorder that is a form of dwarfism
  31. Huntington's disease
    a degenerative disorder of the nervous system that usually does not appear until 35-45 years of age.
  32. amniocentesis
    a test for a genetic disorder for an unborn child.
  33. chorionic villus sampling
    a procedure performed to test for a genetic disorder
  34. ultrasound imaging
    a test used to find anatomical deformities that uses sound waves to produce a picture
  35. complete dominance
    a type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable
  36. incomplete dominance
    a type of inheritance in which the phenotype of a heterozygote (Aa) is intermediate between the phenotypes of the two types of homozygotes (AA and aa)
  37. ABO blood group
    involves three alleles of a single gene. These three alleles, in various combinations, produce four phenotypes: a person's blood type may be either O,A,B, or AB
  38. codominant
    inheritance pattern in which he heterozygote expresses the distinct trait of both alleles
  39. pleiotropy
    the control of more than one phenotypic characteristic by a single gene
  40. polygenic inheritances
    the additive effects of two or more genes on a single phenotypic character
  41. chromosome theory of inheritance
    stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns
  42. linked genes
    genes located close together on the same chromosome tend to be inherited together
  43. recombination frequency
    the percentage of recombinants
  44. sex chromosomes
    a chromosome that determines whether an organism is male or female using X and y
  45. sex-linked gene
    a gene located on either sex chromosome
  46. hemophilia
    a sex-linked recessive trait with a long, well documented history. lacking one or more of the proteins required for blood clotting
  47. red-green color blindness
    a recessive sex-linked disorder that is a malfunction of light-sensitive cells in the eyes
  48. Duchenne muscular dystrophy
    a sex-linked recessive disorder that has a condition characterized by a progressive weakening of the muscles and loss of coordination
Card Set
Chapter 9
patterns of inheritance