a notes on dominant gene action

1. AQU4601 GENETIC AND
STOCK MANIPULATION
GENETIC CONCEPT IN FISH BREEDING :
DOMINANT GENE ACTION
23 JULY 2019
© Dr. Shahreza, PPSPA, UMT
Dr. Shahreza Md. Sheriff
School of Fisheries and Aquaculture Sciences
UMT
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2. Objective
To expose students on the basic concepts of genetics
(gene interaction – dominant gene action) and its
relationship with fish breeding
© Dr. Shahreza Md. Sheriff, PPSPA, UMT AQU4601 2019
Learning outcome
At the end of the session, students should be able to
explain about Dominant Gene action in a fish
breeding program
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3. QUESTION IN FISH BREEDING
How can these
characteristics are
inherited ?
How can new
characteristics
develop in a fish?
How can fish have
different physical
characteristics ?
© Dr. Shahreza Md. Sheriff, PPSPA, UMT AQU4601 2019
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4. Zygote (2n)
Fertilization
Chromosome from male and
female parent carrying certain
genes is transferred to the
offspring through sperm (male
parent) and egg (female parent)
Contribution of genetic information
from the parents to their offspring.
(Half of the genetic information from
the male and half from the female)
2N
=
BASIC GENETIC CONCEPTS – GENE INHERITANCE
© Dr. Shahreza Md. Sheriff, PPSPA, UMT
Male
Gamete (n)
Female
Gamete (n)
AQU4601 2019
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5. The physical characteristics
that is expressed by the
genes
Gene that controls the physical
characteristics of an organism
© Dr. Shahreza Md. Sheriff, PPSPA, UMT
BASIC GENETIC CONCEPTS – GENOTYPE AND PHENOTYPE
2N
Heterozygous
A pair of different gene
located at the same
chromosome
Homozygous
A pair of the same gene
located at the same locationA A
A a
AQU4601 2019
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6. Occurs when dominant allele is stronger and express its phenotypic
(physical characteristics) without considering the type of its paired allele
Dominant gene action can produce 3 genotype and 2 phenotype
PhenotypeGenotype
Dominan
Dominan
Resesif
Homozygous Dominant (AA)
Heterozygous (Aa)
Homozygous Recessive (aa)
2N
X
A a
AA
Aa
aa
2 Types of Phenotype
3 Types of Phenotype
© Dr. Shahreza Md. Sheriff, PPSPA, UMT AQU4601 2019
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7. A A
Heterozygous
Homozygous Dominant
A pair of dominant genes located at the same
location (locus) in a chromosome
The expressed characteristics will follow the
dominant traits
A pair of different genes located at the same
location (locus)
The expressed characteristics will follow the
dominant traits due to the presence of
dominant gene (A)
A a
A A
a a
Homozygous Recessive
A pair of recessive genes located at
the same location (locus) in a
chromosome
The expressed characteristics will
follow the recessive traits due to
the present of both recessive genes
a a
Phenotype :
Genotype :
A a
Phenotype :
Genotype :
Phenotype :
Genotype :
© Dr. Shahreza Md. Sheriff, PPSPA, UMT AQU4601 2019
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8. AA Aa AA Aa
X
A A A a
Genotype : 50% AA
Phenotype : 100% Dominant
© Dr. Shahreza Md. Sheriff, PPSPA, UMT
♀
Female
♂
Male
Phenotype :
Genotype :
A
A
A a
Female
♀♂male
PUNNET SQUARE
A AA
AA A
a
a
HOW GENE ACTION ARE DETERMINED ?
Conducted using Punnet Square
AQU4601 2019
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9. X
A a
AA Aa aa
AA Aa aa
X
A a
© Dr. Shahreza Md. Sheriff, PPSPA, UMT
Next week
AQU4601 2019
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