Mendelian Genetics

Hybrids

Any offspring resulting from the breeding of two genetically distinct individuals.

F1 Generation

Results from the cross pollination of two parent (P) plants, and it contains all purple flowers.

F2 Generation

Results from the self-pollination of F1 plants and contains 75% purple flowers and 25% white flowers.

Dominant

The allele of a gene that masks or suppresses the expression of an alternate allele; the trait appears in the heterozygous condition

Recessive

An allele that is masked by dominant allele, does not appear in the heterozygous condition

Monohybrid cross

Genetic cross involving a single pair of genes (one trait) parents differ by a single trait

punnett square

• Useful tool to do genetic crosses

• Used to predict the genotypes and phenotypes of the offspring

Principle of Dominance

One allele masked another; one allele was dominant over the other in the F1 generation.

Principle of Segregation

When gamete is formed, the pairs of hereditary factors (gametes) become separated, so that each sex cell receives only one kind of gene.

Cystic Fibrosis

• Is a lethal genetic disease affecting Caucasians caused by mutant recessive gene

• This disease affects transport in tissues – mucus is accumulated in lungs, causing infections.

Gaucher Disease

• Is a rare genetic disease, it causes lipid-storage disorder

• It is the most common genetic disease affecting Jewish people of Eastern European ancestry.

Dihybrid Cross

Mating that involves parents that differ in two genes (two independent traits)

Principle of independent assortment

• Members of one gene pair segregate independently from other gene pairs during gamete formation

• Genes get shuffled – these many combinations are one of the advantages of sexual reproduction

Genetic traits

• Are characteristics that are encoded in DNA

• Most forms of albinism are recessive, which is why the child’s parents were able to pass the trait to him without exhibiting the condition themselves

Mendelian inheritance

• Refers to the inheritance of traits controlled by a single gene with two alleles.

• The pattern of inheritance of Mendelian traits depends on whether the traits are controlled by genes on autosomes, or by genes on sex chromosomes.

Albinism

  Controlled by a single autosomal gene with two alleles.