important vocabulary genotype phenotype two alleles make up one genotype alleles are either...
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Important Vocabulary
Genotype Phenotype
Two alleles make up one genotype Alleles are either dominant or recessive
There are exceptions to these rules that will be discussed
Important Vocabulary Genotypes are heterozygous or
homozygous
HH – homozygous dominant
Hh – heterozygous
hh – homozygous recessive
Gregor Mendel developedmany of the principles ofgenetics during his researchon pea plants
Monohybrid CrossA cross between parents that are homozygous
for different alleles of one trait
Complete Dominance – the dominant allele is completely dominant over the recessive allele
#1 - Complete DominanceP: RR rrF1: Genotype Phenotype Type of Genotype
Rr red heterozygousF1 Cross: Rr RrPunnett Square:
F2: Genotype Phenotype Type of GenotypeRR red homozygousRr red heterozygousRr red heterozygousrr white homozygous
RR Rr
Rr rr
R
r
R r
F2 Genotypic Ratio:1 RR : 2 Rr : 1 rrF2 Phenotypic Ratio:3 red: 1 white
Monohybrid CrossA cross between parents that are homozygous
for different alleles of one trait
Incomplete Dominance – the dominant and recessive allele blend together
Monohybrid CrossA cross between parents that are homozygous
for different alleles of one trait
Codominance – both alleles are equally dominant
Complete Dominance
Dihybrid CrossA cross between parents that are homozygous
for different alleles of two traits
#8 - Complete DominanceP: yyrr YYRRF1: Genotype Phenotype Type of Genotype
YyRr yellow/round heterozygousF1 Cross: YyRr YyRrPunnett Square:
yR
yr
YR
Yr
YYRR YYRr YyRR YyRr
YYRr YYrr YyRr Yyrr
YyRR YyRr yyRR yyRr
YyRr Yyrr yyRr yyrr
YR Yr yR yr
F2: Genotype Phenotype9 Y_R_ yellow/round3 Y_rr yellow/wrinkled3 yyR_ green/round1 yyrr green/wrinkled
Sex Linkage
Sex linked genes are located on either the X or Y chromosome
Most sex linked genetic disorders areX-linked
#12 - Sex LinkageP: XHY XHXh
Punnett Square:
F1: Genotype Phenotype Sex Type of GenotypeXHXH normal F homozygousXHXh carrier F heterozygousXHY normal M hemizygousXhY hemophilia M hemizygous
XHXH XHXh
XHY XhY
XH
Y
XH Xh
#15 - Blood TypingP: IAi IBiPunnett Square:
F1: Genotype PhenotypeIAIB ABIAi AIBi Bii O
IAIB IAi
IBi ii
IA
i
IB i
PolygenicInheritance
Examples:Skin/Eye/Hair Color, Height/Body Shape,Rh (+/- Blood), etc.
Most human traits are polygenically inherited
PedigreesExample:You are a normal female (homozygous). Both of your parents are normal. Your younger brother is normal and your older brother has hemophilia.
You!
XHXh XHY
XHYXhY XHXH
#19 - Chromosome Mapping
A B C D E
A - 8 12 4 1
B 8 - 4 12 9
C 12 4 - 16 13
D 4 12 16 - 3
E 1 9 13 3 -
Gene
Gene
Recombinationsper 100
fertilized eggs
D EA B C
3 1 8 4
16