!! GENETICS!! --- Part 1

Gregor Johann Mendel (July 20, 1822 – January 6, 1884) was a German-speaking Silesian scientist who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance. These laws initiated the modern science of genetics.

Mendel's laws

• The principle of segregation (First Law): The two members of a gene pair (alleles) segregate (separate) from each other in the formation of gametes. Half the gametes carry one allele, and the other half carry the other allele.
• The principle of independent assortment (Second Law): Genes for different traits assort independently of one another in the formation of gametes.

Vocabulary

• Pure Line - a population that breeds true for a particular trait
• Phenotype - literally means "the form that is shown"; it is the outward, physical appearance of a particular trait
• Dominant - the allele that expresses itself at the expense of an alternate allele; the phenotype that is expressed in the F1 generation from the cross of two pure lines
• Recessive - an allele whose expression is suppressed in the presence of a dominant allele; the phenotype that disappears in the F1 generation from the cross of two pure lines and reappears in the F2 generation
• Allele - one alternative form of a given allelic pair; tall and dwarf are the alleles for the height of a pea plant; more than two alleles can exist for any specific gene, but only two of them will be found within any individual
• Allelic pair - the combination of two alleles which comprise the gene pair
• Homozygote - an individual which contains only one allele at the allelic pair
• Heterozygote - an individual which contains one of each member of the gene pair
• Genotype - the specific allelic combination for a certain gene or set of genes
• F1 - First generation offspring
• P - Parental generation
• Backcross - Offspring mating with parents 

* Somatic cell --- Body cell, anything but not sex cell. 

Cell division: meiosis/ 46 in total of chromosomes, 23 pairs