Mendelian Genetics

Mendel first reported results from his experiments on garden peas in

1866

Mendel’s laws of inheritance were independently rediscovered by which 3 scientist?

Hugo Devries, Carl Erich Correns, Erich Von Tschermak

is a branch of genetics, which is concerned with the proper selection

Breeding

use of the traits of the parents to produce offspring with predictable and desirable traits for the improvement of animals in general.

Breeding

carry the genetic information that is passed from parent cell to offspring /daughter cell one generation to the next, via meiosis, for gametogenesis, a situation where genes are segregated and can assort resulting to new individuals

Genes

genes that does not change during the process, but the combined number resulting to traits can due to segregation and assortment of genes.

Individual genes

An individual heterozygous for one pair of genes (Aa) is called

Monohybrid

A cross of 2 individuals that are heterozygous for one pair of genes is called a

Monohybrid cross

is one of the gene/allele of a specific locus on homologous chromosomes, overpowering the expression of the other allele.

Dominant allele

is one of the gene whose expression is prevented/overpowered by the dominant allele.

Recessive allele

physical expression of trait

Phenotype

unit factors representing units of inheritance

Genes

alternative forms of a single gene

Alleles

genetic make up of an individual

Genotype

identical alleles constituting the genotype

Homozygote

different alleles constituting the genotype

Heterozygote

The simplest cross involving one pair of contrasting traits.

Monohybrid cross

are controlled by unit factors that exists in pairs in individual organisms.

Genetic characters

Mendel’s first three postulates:

• Units factors in pairs

• Dominance/Recessiveness

  • Segregation

It shows the genotypes and phenotypes from the recombination of gametes during fertilization.

Punnett square

Four parts of the law of segregation

1. Alternative versions of genes account for variations in inherited characters.

2. For each characteristic, an organism inherits two genes, one from each parent.

3. If the two alleles differ, then one (dominant allele), is fully expressed in the organism’s appearance; the other (recessive allele), has no noticeable effect on the organism’s appearance.

4. The two genes for each character segregate during gamete production.

The organism of the dominant phenotype, but unknown genotype, is crossed to a homozygous recessive individual

The test cross

A cross involving two pairs of contrasting traits. It is also known as the two-factor cross.

Dihybrid cross

The emergence of one trait will not affect the emergence of the other. During gamete formation, segregating pairs of unit factors assort independently of each other.

Mendel’s Fourth Postulate

described the basis for inheritance of phenotypic expression.

Mendel’s Postulate

Correlation between Mendelian genetics and behaviors of the chromosomes

a. unit factors in pairs

b. segregation of unit factors during gamete formation

c. Independent assortment of segregating unit factors