Introduction to genetics chapter 11
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Introduction To Genetics- Chapter 11. I. The work of Gregor Mendel. A. Gregor Mendel was born in 1822 and after becoming a priest; Mendel was a math teacher for 14 years and a monastery. Mendel was also in charge of the monastery garden. . 1. Mendel carried out his work with garden peas.

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Introduction To Genetics- Chapter 11

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Introduction to genetics chapter 11

Introduction To Genetics- Chapter 11


I the work of gregor mendel

I. The work of Gregor Mendel

A. Gregor Mendel was born in 1822 and after becoming a priest; Mendel was a math teacher for 14 years and a monastery. Mendel was also in charge of the monastery garden.

.


Introduction to genetics chapter 11

1. Mendel carried out his work with garden peas


Introduction to genetics chapter 11

2. Fertilization is the fusion of an egg and a sperm.

3. True breeding plants are plants that were allowed to self-pollinate and the offspring would be exactly like the parent.


Genes and dominance

Genes and Dominance

1. The different forms of a gene is called and an alleles.

2. The principal of dominance states that some alleles are dominant and others are recessive.


Introduction to genetics chapter 11

Pinky Finger Traits

At John Burke High School they tested dominant and recessive traits in our school population. We tested pinky finger traits, whereby, the bent finger is dominant and the straight finger is recessive.


C segregation

C. Segregation

1. Each trait has two genes, one from the mother and one from the father.

2. Traits can be either dominant or recessive.

3. A dominant trait only needs one gene in order to be expressed.


Introduction to genetics chapter 11

4. A recessive trait needs two genes in order to be expressed.


Introduction to genetics chapter 11

5. Egg and sperm are sex cells called gametes.

6. Segregation is the separation of alleles during gamete formation.


Ii probability and punnett squares

II. Probability and Punnett Squares

A. Genetics and Probability

1. The likelihood that a particular event will occur is called probability.

2. The principals of probability can be used to predict the outcome of genetic crosses.


B punnett squares

B. Punnett Squares

1. The gene combination that might result from a genetic cross can be determined by drawing a diagram known as a Punnett square.

2. Punnett squares can be used to predict and compare the genetic variations that will result from a cross.


Introduction to genetics chapter 11

3. Each trait has two genes- one from the mother and one from the father.

4. Alleles can be homozygous – having the same traits.

5. Alleles can be heterozygous- having different traits.


Introduction to genetics chapter 11

6. Physical characteristics are called the phenotype.

7. Genetic make up is the genotype.


Iii exploring mendalian genetics

III. Exploring Mendalian Genetics

A. Independent assortment

1. Genes segregate independently.


Introduction to genetics chapter 11

2. The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes.

3. Independent assortment helps account for the many genetic variations observed in plants, animals and other organisms.


B a summary of mendel s principals

B. A summary of Mendel’s Principals

1. Genes are passed from parent to offspring.

2. Some forms of a gene may be dominant and others recessive.


Introduction to genetics chapter 11

3. In most sexually producing organisms, each adult has two copies of each gene- one from each parent. These genes are segregated from each other when gametes are formed.

4. The alleles for different genes usually segregate independently of one another.


C beyond dominance and recessive alleles

C. Beyond Dominance and Recessive alleles

1. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

2. Cases in which one allele is not completely dominant over another are called incomplete dominance.


Introduction to genetics chapter 11

a. Example: White (W) and Red (R) is both dominate. If WW X RR the F1 generation would be WR= pink.


Introduction to genetics chapter 11

3. Codominance is when both alleles contribute to the phenotype.

Example: Feather colors


Introduction to genetics chapter 11

4. Many genes have more than two alleles and are referred to have multiple alleles.

a. This means that more than two possible alleles exist in a population. Example: colors of rabbits see page 273.


Introduction to genetics chapter 11

5. Traits that are controlled by two or more genes are said to be polygenic traits, which means, “having many genes.”

a. Example: eye color has many different genes.


Introduction to genetics chapter 11

D. Applying Mendel’s principles

1. Mendel’s principals do not only apply to plants.


Meiosis

Meiosis

A. Chromosome number

1. Every individual has two sets of chromosomes. One from the mother one from the father. When the chromosomes pair up for the same trait they are called homologous chromosomes.


Introduction to genetics chapter 11

2. A cell that contains homologous chromosomes (2 genes) is said to be diploid/ 2n.

3. Gametes (egg /sperm) have only one chromosome and are said to be haploid/ n.


B phases of meiosis

B. Phases of Meiosis

1. Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

2. Meiosis I- ****The homologous chromosomes line up BUT then they CROSS OVER, exchanging genetic information.


Introduction to genetics chapter 11

3. Meiosis II- The two cells produced by meiosis I now enter a second meiotic division. The final product = start with 1 cell with 46 chromosomes and get 4 DIFFERENT cells each with 23 chromosomes.

Go to Internet: www.SciLinks.org code cbn-4114 to view meiosis.


V linkage and gene maps

V. Linkage and gene maps

A. Gene linkage

1. Thomas Hunt Morgan research on fruit flies led him to the principal of linkage.

2. Morgan discovered that many genes appeared “linked” together.


Introduction to genetics chapter 11

3. It is the chromosomes, however, that assort independently not individual genes.

4. Mendel DID miss gene linkage.


Introduction to genetics chapter 11

5. Even though if two genes are found on the same chromosome this does not mean they are linked forever. Crossing over can occur.

6. Crossing over creates genetic diversity.


Introduction to genetics chapter 11

7. A gene map shows the relative location of each gene. See page 280 figure 11.9


The end

THE END


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