Download Gregor Mendel

Gregor Mendel
The term “genetics” (in Greek, means to generate) was coined by William Bateson
in 1905.
Original Mendelian definition of the “gene” (word coined by Johanssen from
“genetics”):That inherited unit located on chromosomes which determines a
biological characteristic. A unit of function and mutation.
The gene is a substance that satisfies two essential requirements:
1) It is inherited between generations in such a way that each descendent has a
physical copy of this material.
2) It provides information to its carriers in respect to structure, function, and
other biological attributes.
Mendel’s First Law (principle
of allelic segregation):
Alleles of each gene segregate
(separate) at the time of meiosis
(gamete formation), so that half
the gametes carry one allele
and half carry the other.
Backcrosses
Dd × DD
Testcrosses
DD × dd
D d
D DD Dd
D
d Dd
Dd × dd
Dd × dd
D d
d Dd dd
D d
d Dd dd
AaBb × aabb
n=2
22 = 4
1:1:1:1
To test for genotype (heterozygosity)
of a dominant phenotype using a
testcross parent (dd)
P. R. = 1
P. R. = 1:1
AaBbCc × aabbcc
n=3
23 = 8
1:1:1:1:1:1:1:1
homologs
tetrad
D = Tall (dominant) d = Dwarf (recessive)
Include ratios before gametes, phenotypes, and genotypes. Circle gametes.
P.R. = Phenotypic ratio
G.R. = Genotypic ratio
Tall x Tall
Tall x Dwarf
DD x DD
DD x dd
Gametes _____
_____
____
_____
Progeny
Progeny
Pheno.
__________________ __________________
Geno.
__________________ __________________
P.R.
__________________ __________________
G.R.
__________________ __________________
Tall x Tall
Tall x Dwarf
DD x Dd
Dd x dd
Gametes _______ _______
_______ _______
Progeny
Progeny
Pheno.
_________________
_________________
Geno.
_________________
_________________
P.R.
_________________
_________________
G.R.
_________________
_________________
Tall x Tall
Dwarf x Dwarf
Dd x Dd
dd x dd
Gametes _______ _______
_______ _______
Progeny
Progeny
Pheno.
_________________
_________________
Geno.
_________________
_________________
P.R.
_________________
_________________
D = Tall (dominant)
d = Dwarf (recessive)
Include ratios before gametes, phenotypes, and genotypes. Circle gametes.
P.R. = Phenotypic ratio G.R. = Genotypic ratio
Tall x Tall
Tall x Dwarf
DD x DD
DD x dd
Gametes 1/1 D x 1/1 D
1/1 D x 1/1 d
Pheno.
Geno.
P.R.
G.R.
Gametes
Pheno.
Geno.
P.R.
G.R.
Gametes
Pheno.
Geno.
P.R.
G.R.
Progeny
_1/1 Tall
_1/1 DD
1
1
Tall x Tall
DD x Dd
1/1 D x 1/2 D 1/2 d
Progeny
1/1 Tall
1/2 DD 1/2 Dd
1
1:1
Tall x Tall
Dd x Dd
1/2 D 1/2 d x 1/2 D 1/2 d
Progeny
3/4 Tall ¼ Dwarf
1/4 DD 2/4Dd 1/4dd
3:1
1:2:1
Progeny
1/1 Tall
1/1 Dd
1
1
Tall x Dwarf
Dd x dd
1/2 D 1/2 d x 1/1 d
Progeny
1/2 Tall 1/2 Dwarf
1/2 Dd 1/2 dd
1:1
1:1
Dwarf x Dwarf
dd x dd
1/1 d x 1/1 d
Progeny
1/1 Dwarf
1/1 dd
1
1
Using the information given, fill in all blanks below. Circle each gamete. Autosomal
trait in Drosophila melanogaster.
V = Normal wings (dominant); v = Vestigial wings (recessive).
P Phenotypes
Normal
x
Vestigial
Genotypes
VV
x
vv
Gametes
x
_________
F1 Phenotypes
x
_________
Genotypes
x
_________
Gametes
___________
x
____ ____
F2 Phenotypes
______________________________________
Genotypes
______________________________________
F2 Phenotypic ratio
______________________________________
F2 Genotypic ratio
______________________________________
Use the information above to make a testcross below.
F1 Parent
Phenotypes
Genotypes
Gametes
x
x
x
x
Testcross parent
_________
__
_________
Testcross Progeny
Phenotypes
Genotypes
__________
_________
__________
_________
Testcross phenotypic ratio _______________________________________
Testcross genotypic ratio _______________________________________
Using the information given, fill in all blanks below. Circle each gamete. Autosomal
trait in Drosophila melanogaster.
V = Normal wings (dominant); v = Vestigial wings (recessive).
P Phenotypes
Normal
x
Vestigial
Genotypes
VV
x
vv
Gametes
1/1 V
x
1/1 v
F1 Phenotypes
Genotypes
Gametes
Normal
Vv
1/2 V 1/2 v
F2 Phenotypes
Genotypes
F2 Phenotypic ratio
F2 Genotypic ratio
3 Normal
1 VV 2 Vv
3:1
1:2:1
x
x
x
Use the information above to make a testcross below.
F1 Parent
x
Phenotypes
Normal
x
Genotypes
Vv
x
Gametes
1/2 V 1/2 v
x
Testcross Progeny
Phenotypes
Normal
Vestigial
Testcross phenotypic ratio
1:1
Testcross genotypic ratio
1:1
Normal
Vv
1/2 V 1/2 v
1 Vestigial
1 vv
Testcross parent
Vestigial
vv
1/1 v
Genotypes
Vv
vv
Using the information given, fill in all blanks below. Circle each gamete. Autosomal trait in Pisum sativum.
T = Axial pods (dominant); t = Terminal pods (recessive).
P Phenotypes
Axial
x
Terminal
Genotypes
TT
x
tt
Gametes
x
____________
F1 Phenotypes
x
____________
Genotypes
x
____________
Gametes
x
____________
F2 Phenotypes
_________________________________________
Genotypes
_________________________________________
F2 Phenotypic ratio
_________________________________________
F2 Genotypic ratio
_________________________________________
Use the information above to make a testcross below.
Testcross
F1 Parent
Phenotypes
Genotypes
Gametes
Phenotypes
____________________
____________________
Testcross phenotypic ratio
Testcross genotypic ratio
x
Testcross parent
x
__________
x
x
__________
Testcross Progeny
Genotypes
____________________
____________________
_____________________________
_____________________________
Using the information given, fill in all blanks below. Circle each gamete. Autosomal trait in Pisum sativum.
T = Axial pods (dominant); t = Terminal pods (recessive).
P Phenotypes
Axial
x
Terminal
Genotypes
TT
x
tt
Gametes
1/1 T
x
1/1 t
F1 Phenotypes
Axial
x
Axial
Genotypes
Tt
x
Tt
Gametes
1/2 T 1/2 t
x
1/2 T
F2 Phenotypes
3/4 Axial 1/4 Terminal
Genotypes
1/4 TT 2/4 Tt 1/4 tt
F2 Phenotypic ratio
3:1
F2 Genotypic ratio
1:2:1
Use the information above to make a testcross below.
Testcross
F1 Parent
Phenotypes
Genotypes
Axial
Tt
Gametes
1/2 T
Phenotypes
1/2 Axial
1/2 Terminal
Testcross phenotypic ratio
Testcross genotypic ratio
x
x
x
1/2 t
1/2 t
Testcross parent
Terminal
tt
x
1/1 t______
Testcross Progeny
Genotypes
1/2 Tt
1/2 tt
1:1
1:1
Include ratios before gametes, phenotypes, and genotypes. Circle gametes.
RR = Red, RR' = Roan, R'R' = White (Example of codominance; however,
ratios similar to semidominance in crosses).
Red X Red
Red X Roan
Geno.
________ X ________
________ X ________
Gametes
________ X ________
________ X ________
Progeny
Progeny
Pheno.
____________________
____________________
Geno.
____________________
____________________
P.R.
____________________
____________________
G.R.
____________________
____________________
Red
X White
Geno.
________ X ________
Gametes
________ X ________
Progeny
Pheno.
___________________
Geno.
___________________
P.R.
___________________
G.R.
___________________
Roan
X Roan
________ X ________
________ X ________
Progeny
____________________
____________________
____________________
____________________
Roan X White
White X White
Geno.
________ X ________
________ X ________
Gametes
________ X ________
________ X ________
Progeny
Progeny
Pheno.
____________________
____________________
Geno.
____________________
____________________
P.R.
____________________
____________________
G.R.
____________________
____________________
RR = Red, RR' = Roan, R'R' = White
Red
X
Red
RR
X RR
1/1 R
X 1/1 R
Progeny
1/1 Red
1/1 RR
1
1
Geno.
Gametes
Pheno.
Geno.
P.R.
G.R.
Red
Geno.
Gametes
Pheno.
Geno.
P.R.
G.R.
X White
RR
X R′R′
1/1 R
X 1/1 R′
Progeny
1/1 Roan
1/1 RR′
1
1
Roan
Geno.
Gametes
Pheno.
Geno.
P.R.
G.R.
X White
RR′
X
R′R′
1/2 R 1/2 R′
X 1/1 R′
Progeny
1/2 Roan 1/2 White
1/2 RR′ 1/2 R′R′
1:1
1:1
Red
X
RR
1/1 R
Roan
X
X
Progeny
1/2 Red
1/2 RR
1:1
1:1
Roan
X
RR′
X
1/2 R 1/2 R′ X
RR′
1/2 R 1/2 R′
.
1/2 Roan
1/2 RR′
.
.
.
.
Roan
RR′
1/2 R 1/2 R′
.
.
Progeny
1/4 Red 2/4 Roan 1/4 White
1/4 RR 2/4 RR′
1/4 R′R′
1:2:1
1:2:1
White
R′R′
1/1 R′
X
X
X
.
.
.
.
White
R′R′
1/1 R′
.
.
.
Progeny
1/1 White
1/1 R′R′
1
1
.
.
.
.
Using the information given, fill in all blanks below. Circle each gamete.
Illustrate crosses and results for semidominant inheritance of an autosomal trait in cattle.
RR = Red; RR′ = Roan; R′R′ = White
P Phenotypes
Genotypes
Gametes
F1 Phenotypes
Genotypes
Gametes
F2 Phenotypes
Genotypes
F2 Phenotypic ratio
F2 Genotypic ratio
RR
X
X
X
.
R′R′
.
.
X
X
X
Use the information above to make a testcross below:
F1 Parent
X
Phenotypes
X
Genotypes
X
Gametes
X
Testcross Progeny
Phenotypes
.
.
.
.
.
.
.
Testcross Parent
.
.
.
Genotypes
.
.
Testcross phenotypic ratio
Testcross genotypic ratio
.
.
Using the information given, fill in all blanks below. Circle each gamete.
Illustrate crosses and results for semidominant inheritance of an autosomal trait in cattle.
RR = Red; RR′ = Roan; R′R′ = White
P Phenotypes
Genotypes
Gametes
F1 Phenotypes
Genotypes
Gametes
Red
RR
1/1 R
1/2 R
Roan
RR′
1/2 R′
F2 Phenotypes
1/4 Red
2/4 Roan
Genotypes
1/4 RR
2/4 RR′
F2 Phenotypic ratio
1:2:1
F2 Genotypic ratio
1:2:1
X
X
X
X
X
X
White
R′R′
1/1 R′
.
.
.
Roan
RR′
1/2 R
1/2 R′
1/4 White
1/4 R′R′
.
.
.
.
.
.
.
Testcross
Cannot make a testcross because you do not have an organism that is homozygous
recessive for all genes in question.
A Horse with the
BASE color of:
A Red based horse with no black gene and no dilution gene
With ONE crème dilution
gene added becomes:
A sorrel/chestnut horse that received one copy of the crème
dilution gene from one of its parents, giving it a coat ranging
in color from pale cream, to golden, to chocolate and has a
white mane and tail.
With TWO crème dilution
genes added becomes:
A sorrel/chestnut horse that received one copy of the crème
gene from both of its parents, and has pink skin, blue eyes,
cream to nearly white hair coat, and a white mane and tail.
A Horse with the
BASE color of:
A Black based horse with the "bay" gene, which restricts the black to
the mane, tail and legs (also called black "points") and no dilution gene
With ONE crème dilution
gene added becomes:
A Bay horse that received one copy of the crème dilution gene from
one of its parents, giving it a diluted hair coat (the color can range
from very pale cream, to gold, to a dark "smutty" color,) and has
black "points".
With TWO crème dilution
genes added becomes:
A Bay horse that received one copy of the crème gene from both of
its parents, and has pink skin, blue eyes, a cream to white colored
coat and a darker mane and tail (often orange or red tinted).
A Horse with the
BASE color of:
A Black based horse with no "bay" gene, and no dilution gene,
ranging from "true" black to brown in appearance.
With ONE crème dilution
gene added becomes:
A Black horse that received one copy of the crème dilution gene
from one of its parents, but probably looks no different than any
other black or brown horse.
With TWO crème dilution
genes added becomes:
A Black horse that received one copy of the crème gene from both
of its parents, possessing pink skin, blue eyes, and an orange or
red cast to the entire hair coat.
Colors
Mixed
Cremello
Sorrel
100%
Palomino
Bay
Perlino
Palomino
Buckskin
Smoky
Black
50% Palomino
50% Sorrel
50% Buckskin,
50% Bay
100%
Buckskin
Black
50% Smoky
black,
50% Black
100%
Smoky black
Palomino 50%
Palomino
50%
Cremello
Buckskin
Smoky
Cream
50%
Palomino,
25% Sorrel,
25% Cremello
50%
Buckskin,
50%
Perlino
50%
Buckskin,
25%
Bay,
25%
Perlino
Colors
Mixed
Cremello
Perlino
Smoky
Cream
Cremello 100%
Cremello
Smoky
Cream
Buckskin
Smoky
Black
50%
Smoky black,
25% Black,
25% Smoky
cream
50%
Smoky black,
50%
Smoky Cream
Smoky
Black
Perlino
Palomino
50%
Cremello,
50%
Palomino
100% Perlino
50% Perlino,
50% Buckskin
100% Smoky
Cream
50% Smoky
Cream,
50% Smoky
Black