BIOL 100 exam 2 - CH 20

  1. Trait
    expressed characteristic
  2. Allele
    an alternative form of a gene.

    determines the variation of a trait (i.e. blue eyes vs brown eyes)
  3. Homozygous
    2 copies of the same allele
  4. Heterozygous
    1 copy of one allele and 1 copy of a different allele
  5. Dominant Allele
    allele that shows up regardless if you have 1 or 2 copies
  6. Recessive Allele
    allele that can only be seen if there are 2 of them
  7. Genotype
    specific alleles that an individual has

    "what it is"
  8. Phenotype
    the physical appearance of the "allele"

    "what it looks like"
  9. Pedigree
    family tree of a trait expression

    determination of ancestors' genotype
  10. Carrier
    person who has the gene but does NOT exhibit the trait
  11. Complete Dominance
    the dominant allele in a heterozygous person completely masks the recessive allele
  12. Codominance
    both alleles are expressed in a heterozygous individual

    i.e. blood type ABO
  13. Incomplete Dominance
    heterozygous individual is a blend of 2 genes

    i.e. Red Flower and White Flower make a Pink Flower
  14. Pleiotropy

    one gene having many effects
  15. Multiple Alleles
    3 or more alleles form a particular gene

    i.e. the alleles governing the ABO blood types
  16. Polygenic Inheritance
    more than one gene controlling a single trait

    i.e. height, skin color, eye color
  17. X-Linked Genes
    genes carried on the x chromosome

    have no corresponding allele on the y chromosome

    will be expressed in a male, and in a female (if she is homozygous)
  18. Deletion
    pertaining to chromosomes, the loss of a nucleotide or segment of a chromosome
  19. Duplication
    pertaining to chromosomes, the duplication of a region of a chromosome that often results from fusion of a fragment from a homologous chromosome
  20. Amniocentesis

    a method of prenatal testing for genetic problems in a fetus in which amniotic fluid is withdrawn through a needle so that the fluid can be tested biochemicallyand the cells can be cultured and examined for genetic abnormalities
  21. Chorionic Villi Sampling (CVS)

    a procedure for screening for genetic defects of a fetus by removing a piece of chorionic villi and examining the cells for genetic abnormalities
  22. Law of Segregation
    - During meiosis homologous pairs split

    - 1 egg ends up with 1 set of alleles

    - another egg could end up with another set of alleles

    - i.e. any gamete is equally likely to have any allele (any combo is equally possible)
  23. 2 alleles
    Every person has 23 pairs of chromosomes; therefore, each person has (#?) alleles for each trait.
  24. Hybrid Crosses
    utilizes 2 individuals to determine the inheritance pattern of a Single trait
Card Set
BIOL 100 exam 2 - CH 20
CH 20 Genetics and Human Inheritance