Gene : A sequence of bases that codes for a
polypeptide
There are 64 codons
Genetic code
-
triplets/codons : code for a n amino acid
-
Redundant/degenerate
-
Universal
Allele :
Different versions of the same
genes
Ibase sequence is
slightly different
Alleles count for all within
genetic differences species
·
a
Genome : All of the DNA of an
organism
Ploidy :
refers to the no .
of copies of the genome an
organism has .
<
Haploid :
one copy of genome
Diploid two copies of
:
genome
Chromosomes long :
molecules of DNA containing many genes.
these molecules a re
packaged around protein called histones
histones
The DNA/histone complex becomes further packaged to form a fibre called chromatin .
histones
# Homologous chromosomes :
Have the same
genes at
,
the same loci, but
have some different alleles
f eter
if you inherit I copies
of the same allele of a
gene
you're homozygous
For that
gene
ony yous for
B
gene
Genotype : the alleles carried
for a
particular gene 2 .
g . At or Bb
Phenotype :
the physical features that result from the genotype (e g . . brown eyes)
, Dominant/Recessive allele
↓
L
Dominant alleles -
these show up in the phenotype ,
even in the These are hidden from the phenotype
presence of a
different allele li . e . -when the genotype in the presence of a different allele
is heterozygous)
Codominant :
both alleles a re expressed individually
Example :
flower color in Snap dragon plants
Incomplete/partial dominance : intermediate of both alleles
Phenotype is controlled by 1
gene with 2 alleles
Y
Codes for pigment
an
enzyme that synthesises a RED
("
Function
enzyme
+ =
codesforits
Genotype Phenotype
Non-functional,
enzyme
(W codes foretals
Cryp Red
(u(w White
The heterozygous
-
Cr ,
can't produce enough pigment to appear red w
Pink
1 :2 : 1 ratio
ABO blood
group
:
Phenotype is controlled
by 1 gene with with 3 alleles
It IB To
↑
#* & I are co-dominant
↓ ↓ Codes for
Codes Codes for neither
for antigen antigen B antigen
# & IB are dominant over I A
Genotype Phenotype Test/Back cross
IAI A Organism has dominant phenotype Je g .
.
group
Al
↓
Y
TBTB
A
I
It To
B
To 70 O
>
You breed
-
with
homozygous recessive
IA 70 A Y
test cross/
bask cross
#
B
70 B IV TA It 70
It IO IV I It To
*
[1 +
B
AB
To To To I
I It To It To To IVTO To To
phenotype ratio phenotype ratio A 0 :
A :s = 1 : /
1 : E
polypeptide
There are 64 codons
Genetic code
-
triplets/codons : code for a n amino acid
-
Redundant/degenerate
-
Universal
Allele :
Different versions of the same
genes
Ibase sequence is
slightly different
Alleles count for all within
genetic differences species
·
a
Genome : All of the DNA of an
organism
Ploidy :
refers to the no .
of copies of the genome an
organism has .
<
Haploid :
one copy of genome
Diploid two copies of
:
genome
Chromosomes long :
molecules of DNA containing many genes.
these molecules a re
packaged around protein called histones
histones
The DNA/histone complex becomes further packaged to form a fibre called chromatin .
histones
# Homologous chromosomes :
Have the same
genes at
,
the same loci, but
have some different alleles
f eter
if you inherit I copies
of the same allele of a
gene
you're homozygous
For that
gene
ony yous for
B
gene
Genotype : the alleles carried
for a
particular gene 2 .
g . At or Bb
Phenotype :
the physical features that result from the genotype (e g . . brown eyes)
, Dominant/Recessive allele
↓
L
Dominant alleles -
these show up in the phenotype ,
even in the These are hidden from the phenotype
presence of a
different allele li . e . -when the genotype in the presence of a different allele
is heterozygous)
Codominant :
both alleles a re expressed individually
Example :
flower color in Snap dragon plants
Incomplete/partial dominance : intermediate of both alleles
Phenotype is controlled by 1
gene with 2 alleles
Y
Codes for pigment
an
enzyme that synthesises a RED
("
Function
enzyme
+ =
codesforits
Genotype Phenotype
Non-functional,
enzyme
(W codes foretals
Cryp Red
(u(w White
The heterozygous
-
Cr ,
can't produce enough pigment to appear red w
Pink
1 :2 : 1 ratio
ABO blood
group
:
Phenotype is controlled
by 1 gene with with 3 alleles
It IB To
↑
#* & I are co-dominant
↓ ↓ Codes for
Codes Codes for neither
for antigen antigen B antigen
# & IB are dominant over I A
Genotype Phenotype Test/Back cross
IAI A Organism has dominant phenotype Je g .
.
group
Al
↓
Y
TBTB
A
I
It To
B
To 70 O
>
You breed
-
with
homozygous recessive
IA 70 A Y
test cross/
bask cross
#
B
70 B IV TA It 70
It IO IV I It To
*
[1 +
B
AB
To To To I
I It To It To To IVTO To To
phenotype ratio phenotype ratio A 0 :
A :s = 1 : /
1 : E
