Genetics
Genetics
the study of passing traits from one generation to the next
Heredity
the passing of traits from parent to offspring
Gregor Mendel
an austrian monk who performed experiments with pea plants
Controlled Breeding
Mendel studied genetics by doing this with pea plants
Traits
each form of a characteristic
self-pollination, cross-pollination
Name 2 types of pollination
Self-pollination
when a true breeding plant does this, it always produces offspring with traits that match the parent
Cross-pollination
type of pollination mendel used
Hybrid
plants (or other organisms) are called this if they come from true-breeding parent plants with different forms of the same trait
3:1
ratio always seen when hybrids are cross pollinated
Dominant Trait
a genetic factor that blocks another genetic factor
Recessive trait
a genetic factor that is blocked by the presence of a dominant factor
Gene
a section on a chromosome that has genetic information for one trait,
A segment of DNA on a chromosome
A segment of DNA on a chromosome
Allele
the different forms of a gene. Each chromosome has one allele for every gene on it
Phenotype
how a trait appears
Punnett Square
a tool used to determine traits of future offspring
Genotype
the two alleles that control the phenotype of a trait (HH, hh, or Hh (type of gene)
Homozygous
when the two alleles of a gene are the same
Heterozygous
if the two alleles of a gene are different
Pedigree
a chart of genetic history of a family for several generations
shows phenotypes of genetically related family members, a type of modeling inheritance
shows phenotypes of genetically related family members, a type of modeling inheritance
Incomplete Dominance
when the offspring’s pheonotype is a blend of the parents’ phenotypes
Codominance
occurs when both alleles can be observed in a phenotype
OO
Blood Type O
AB
Blood type AB
AA, Ao
Blood type A
BB, Bo
Blood type B
Polygenic Inheritance
occurs when multiple genes determine the phonotype of a trait Example: skin color is controlled by more than one gene
DNA
an organism’s genetic material
Double Helix
shape of DNA
Nucleotide
a molecule made of a nitrogen base, a sugar, and a phosphate group
Sugar phosphate groups
the groups that form the sides of the DNA ladder
Adenine (A), cytosine (C), thymine (T), and guanine (G)
the nitrogen bases that bond and form the rungs of the ladder
Mutation
a change in the nucleotide sequence of a gene
Exposure to X-rays, ultraviolet light, radioactive materials, and some kinds of chemicals
how mutations can be triggered
Substitution
the C-G base pair has been replaced with a T-A pair
one nitrogen base is replaced by a different one
one nitrogen base is replaced by a different one
Insertion
Three base pairs have been added
one or more nitrogen bases is added to the DNA
one or more nitrogen bases is added to the DNA
Deletion
three base pairs have been removed. Other base pairs will move int to take their place
one of more nitrogen bases is left out of the DNA
one of more nitrogen bases is left out of the DNA