Cellular Basis of Inheritance and Mendelian Inheritance

Animal Genetics

Principles of inheritance in animals.

Animal breeding

Application of genetic principles in the improvement of livestock and poultry.

Qualitative Genetics

Modes of Inheritance -- predict progeny phenotypic distribution based on parental genotypes.

Quantitative Genetics

Assessing genetic merit -- describe traits with statistics to predict next record, genetic merit, response to selection.

Population Genetics

Gene and genotypic frequencies -- predict direction and magnitude of changes in a population.

Phenotype

observed expression of a trait

Genotype

composite of all genes that influence a trait

Environment

all non-genetic factors that influence a trait

Qualitative

• few loci

• discrete phenotypes

• little or no effect of the environment

Quantitative

• many loci

• measured phenotypes

• environmental effect can be larger

Chromosomes

4 cm long

The size of DNA

DNA

1. Adenine

2. Guanine

3. Thymine

4. Cytosine

Four bases of DNA

Purine Bases

• Adenine and guanine

• Two Carbon rings

Pyrimidine bases

• Thymine and cytosine

• A single carbon ring

Nucleotides

Are joined with phosphodiester bond

genetic information

Point Mutations

changes in one or a few nucleotides

Frameshift Mutations

shifts the reading frame of the genetic message so that the protein may not be able to perform its function.

Klinefelter’s Syndrome

•XXY, XXYY, XXXY

•Male

• Sterility

• Small testicles

•Breast enlargement

XYY Syndrome

• Normal male trai

• Often tall and thin

• Associated with antisocial and behavioral problems

Turner’s Syndrome

• X0

• Female

• sex organs don't mature at adolescence

• sterility

• short stature

Genetics

• STUDY OF HEREDITY OR THE WAY IN WHICH TRAITS OF PARENTS ARE PASSED ON TO THE OFFSPRING

GREGOR MENDEL

• 1ST PERSON TO STUDY GENETICS--GARDEN PEAS

• Responsible for the Laws governing Inheritance of Traits

Law of Dominance

• States that on crossing homozygous organisms for single pair of contrasting characters, only one character make its appearance in F1 generation and is named as Dominant character.

• All the offspring will be heterozygous and express only the dominant trait.

Law of Independent Assortment

also known as "Inheritance Law", states that alleles of different genes assort independently of one another during gamete formation.

Different traits are inherited independently of each other, so that there is no relation, for example, between a cat's color and tail l length.

alleles

Genes can have alternate versions called

Mendel's Law of Segregation

The two alleles for each trait separate during gamete formation. This now called:

INCOMPLETE DOMINANCE

ONE GENE DOES NOT HIDE OR MASK THE EFFECT OF THE OTHER GENE IN GENE PAIR--> RESULTS IN MIXTURE OF THE TWO TRAITS.

Codominance

Two alleles are expressed in heterozygous individuals.

Epistasis

Interaction of two or more pair of genes that are not alleles to produce a phenotype that they don’t produce when they occur seperately.

Polygenetic Inheritance

This occurs when there is an additive effect from two or more genes.