Генетика. Mendel’s laws. Genetic interections

Август 4, 2022

Главная
Биология
Генетика. Mendel’s laws. Genetic interections

Содержание

2. QUESTIONS -Mendel's Laws: *Law of Dominans *Law of Segregation *Law of Independent Assortment -Genetic Interactions: allelic
3. Gregor Mendel was: a young priest a science and math teacher Mendel formed the foundation of
4. What he did….. He used pea plants because they have many traits that exist in only
5. He started with purebred (always produces offspring with the same form of a trait as the
6. First Experiment (P generation) Crossed purebred tall plants with purebred short plants. He called it the
7. Monohybrid Cross Р А А а а х G А а F1 А а
8. Law of Dominance In a cross of parents that are pure for contrasting traits, only one
9. Next experiment He allowed the F1 plants to self pollinate In the F2 generation there was
10. F1 А а А а х G А А а а А а А А А
11. Р А А а а х G А а F1 А а А а х G
12. Law of Segregation During the formation of gametes, the two alleles resposible for a trait separate
13. Р АА ВВ аа bb х G АВ аb F1 Аа Bb 100% Dihybrid Cross
14. F1 Аа Bb Аа Bb х G AB Ab aB ab AB Ab aB ab AaBb
15. Dihybrid Cross Law of Independent Assortment Alleles for different traits are passed to offspring independently of
16. He concluded that: individual factors must control the inheritance of traits in peas. They exist in
17. Today we call those factors that control traits genes. They call the different forms of gene
18. ГЕНЕТИКА Genetic Interections
19. The phenomen to alter the phenotypic expression of a gene by the influence of other genes
20. Full Dominance – one of the alleles is dominant and the other recessive
21. Incomplete Dominance- the dominant gene fails to show complete dominancy and the hybrids appear intermediate between
22. Characters of Multiple Alleles They always occupy the same locus in the chromosome and influence the
23. Inheritance of blood groups in man. Blood group A Blood group B P ♀IAI0 × ♂IBIO
24. Human blood groups
25. Non-allelec interaction – is interaction between alleles of different genes present on different chromosomes: -Complementary Genes,
26. Complementary Genes – one must be present for the other to have an operative effect. А_В_
27. Epistasis Epistasis is an interactoin between two non-allelic genes in which one gene supresses the expression
28. Dominant Epistasis (13:3) in Poultry А_вв – Colored аавв – White P ♀AaBb × ♂AaBb aaB_
29. Polygenic Inheritance – each gene has a certain amount of effect and the more number of
30. Height in Man. А1А1А2А2А3А3 – 180 см а1а1а2а2а3а3 – 150 см А1а1А2а2А3а3 А1А1А2а2а3а3 165 см а1а1а2А2А3А3
31. Pleiotropism. A single gene influences more then one phenotypic trait. The phenomenon of multiple phenotypic expressions
33. Скачать презентацию

Слайд 2

QUESTIONS
-Mendel's Laws:
Law of Dominans
Law of Segregation
*Law of Independent

Assortment
-Genetic Interactions: allelic and non allelic
- Multiple Alleles

Слайд 3

Gregor Mendel was:
a young priest
a science and math teacher
Mendel formed

the foundation of genetics, the scientific study of heredity.
Gregor Mendel is a Father of Genetics

Слайд 4

What he did…..
He used pea plants because they have many traits

that exist in only two forms. (tall/short, green seed/yellow seed) and they were self pollinating
He decided to cross plants with opposite forms of a trait, for example, tall plants and short plants.

Слайд 5

He started with purebred (always produces offspring with the same form

of a trait as the parent)
By using purebreds he knew that the offspring's traits would always be identical to that of the parents.

Слайд 6

First Experiment (P generation)
Crossed purebred tall plants with purebred short plants.

He called it the parental generation or P generation.
He called the offspring from this cross the first filial generation (F1) filial meaning “son of”.
In the F1 generation all the plants were tall. The shortness trait had disappeared.

Слайд 7

Monohybrid Cross
Р
А А
а а
х
G
А
а
F1
А а

Слайд 8

Law of Dominance
In a cross of parents that are pure

for contrasting traits, only one form of the trait will appear in the next generation. All the offspring will be heterozygous and express only the dominant trait.

Слайд 9

Next experiment
He allowed the F1 plants to self pollinate
In the

F2 generation there was a mix of tall and short plants.
This occurred even though the parents were all tall.
He found that ¾ of the plants were tall and ¼ of the plants were short.

Слайд 10

F1
А а
А а
х
G
А
А
а
а
А а
А А
А а
а а
F2
А А
А а
А а
а

3 : 1(phenotype)

Слайд 11

Р
А А
а а
х
G
А
а
F1
А а
А а
х
G
А
А
а
а
А а
А А
А а
а а
F2
А А
А

А а

а а

1 2 1

Слайд 12

Law of Segregation
During the formation of gametes, the two alleles resposible

for a trait separate from each other.

Слайд 13

Р
АА ВВ
аа bb
х
G
АВ
аb
F1
Аа Bb
100%
Dihybrid Cross

Слайд 14

F1
Аа Bb
Аа Bb
х
G
AB Ab aB ab
AB
Ab
aB
ab
AaBb
AaBB
AABb
AABB
Aabb
AaBb
AAbb
AABb
aaBb
aaBB
AaBb
AаBB
aabb
aaBb
Aabb
AaBb
9 3 3 1
F2

Слайд 15

Dihybrid Cross Law of Independent Assortment
Alleles for different traits are passed to

offspring independently of one another

Слайд 16

He concluded that:
individual factors must control the inheritance of traits in

peas.
They exist in pairs and the female parent contributes one factor while the male parent contributes the other.

Слайд 17

Today we call those factors that control traits genes.
They call

the different forms of gene alleles

Слайд 18

ГЕНЕТИКА
Genetic Interections

Слайд 19

The phenomen to alter the phenotypic expression of a gene

by the influence of other genes is called Interaction of Genes.
Allelic interaction – is interaction between two alleles of the same gene to change the phenotype:
- complete dominance,
- incomplete dominance,
- codominance,
- multiple alleles.

Слайд 20

Full Dominance – one of the alleles is dominant and the

other recessive

Слайд 21

Incomplete Dominance- the dominant gene fails to show complete dominancy and

the hybrids appear intermediate between the two parents. This was observed by Correns in the “Four o’clock plant Mirabilis jalаpa”.
Co – dominance: both the alleles are equally dominant and hence express themselves equally in a heterozygote.

Слайд 22

Characters of Multiple Alleles
They always occupy the same locus in the

chromosome and influence the same character.
Only two members of such alleles are present at a time in a diploid.
The wild type allele is nearly always dominant while the other mutant alleles in the series may show dominance or there may be an intermediate phenotypic effect.

Multiple Alleles – more than two alleles of a gene occupying the same locus in a given pair of homologous chromosomes are called multiple alleles.

Слайд 23

Inheritance of blood groups in man.
Blood group A Blood group

B
P ♀IAI0 × ♂IBIO

G IA IO IB IO
F1 IAIB(AB), IAIO(A), IBIO(B), IOIO(O)

Слайд 24

Human blood groups

Слайд 25

Non-allelec interaction – is interaction between alleles of different genes

present on different chromosomes:
-Complementary Genes,
-Epistasis,
-Polygenic Inheritance.

Слайд 26

Complementary Genes – one must be present for the other to

have an operative effect.

А_В_ – Red
ааВ_ – White
аавв – White
А_вв – White
P ♀AAbb × ♂aaBB
G Ab aB
F1 AaBв- 100% Red

P ♀AaBb × ♂AaBb
G AB, Ab, AB, Ab
aB, ab aB, ab
F 2 9 : 7
Red : White

Слайд 27

Epistasis
Epistasis is an interactoin between two non-allelic genes in which one

gene supresses the expression of another affecting the same character. The expressed gene is called epistatic, while the supressed gene is said to be hypostatic.

Слайд 28

Dominant Epistasis (13:3) in Poultry
А_вв – Colored
аавв – White P ♀AaBb

× ♂AaBb
aaB_ - White G AB,Ab AB, Ab
A_B_ -White a aB,ab aB,ab
F2 13 : 3
Ratio white : colored
_____
P ♀AABB × ♂aabb
G AB ab
F 1 AaBb – 100% White

Слайд 29

Polygenic Inheritance – each gene has a certain amount of effect

and the more number of dominant genes, the more pronounced is the effect.
In such inheritance the complete expression of a trait is controlled by two or more genes.
A dominant allele of each gene contributes only a unit fraction of the traits and the total phenotypic expression is the sum total or additive or cumulative effect of the dominant alleles of genes or polygenes.

Слайд 30

Height in Man.
А1А1А2А2А3А3 – 180 см
а1а1а2а2а3а3 – 150 см
А1а1А2а2А3а3
А1А1А2а2а3а3 165

см
а1а1а2А2А3А3

Слайд 31

Pleiotropism.
A single gene influences more then one phenotypic trait. The phenomenon

of multiple phenotypic expressions of a single gene is called pleiotropism.
In man a pleiotropic gene has a multiple effect causing a hereditary disease called phenylketonuria.