Download GENETICS NOTES OUTLINE

ENVIRO BIO GENETICS NOTES OUTLINE
I. GENETICS
A. Definition:
B. Gregor Mendel:
Who?
Where?
What?
C. Pea Plants
II. DEFINITIONS
DEFINITION
GENES
DOMINANT TRAIT
RECESSIVE TRAIT
PUNNETT SQUARE
HOMOZYGOUS/PURE
BREED, TRUEBREEDING
HETEROZYGOUS/
HYBRID
GENOTYPE
PHENOTYPE
III. PROBABILITY AND PUNNETT SQUARE
Why are Punnett squares used?
Rule: Dominant letter always capitalized and listed FIRST
Recessive letter always lower case and SECOND
Practice:
1. If a homozygous tall person was crossed with a homozygous short person, what are
probably offspring?
Tall= T
short= t
2. Cross two heterozygous tall parents.
Tall= T
short= t
3. In dogs, wire hair (W) is dominant to smooth (w). Cross a
homozygous wire haired dog with a smooth-haired dog.
Wire hair= W
Smooth hair= w
4. Tongue rolling (T) is dominant to non-tongue rolling (t). Cross a homozygous
tongue-rolling with a heterozygous tongue-rolling.
Tongue-rolling= T
No-tongue roll= t
5. The long-eared allele (L) is dominant to the short-eared allele (l). Cross a homozygous
long ear with a homozygous short-ear. Then cross the F1 generation and give the F2
results.
Long ear= L
Short ear= l
IV. EXPLORING MENDELIAN GENETICS: TWO TRAITS
A. How to figure out possible gametes in a dihybrid cross: use F.O.I.L.!!
B. Ex: Tall is dominant to short. Purple flowers is dominant to white flowers.
Cross a heterozygous tall, heterozygous purple plant with another
heterozygous tall, heterozygous purple plant.
Parent 1: ____________ Parent 2: _____________
TtPp can give gametes: TP, Tp, tP, and tp.
The ratio of a
dihybrid
heterozygous cross
is always:
___________!
V. BEYOND PURE DOMINANCE
A. Define Incomplete dominance:
B. Ex: Cross a red flower with a white flower, showing incomplete dominance, where
R= red and W= white.
C. Define Co-dominance:
Examples:
D. Define Multiple Alleles:
Examples:
E. Define Polygenic Traits:
Examples:
VI. SEX LINKED TRAITS
Sex determination:
Remember:
Any allele on the X chromosome will NOT be masked by
a matching allele on the Y chromosome
Why are sex-linked traits more common in males than females?
Ex: Hemophilia is a recessive, sex-linked disease. Cross a heterozygous normal
female with a normal male.
Normal=
Hemophilia=