General Terms

• Gregor Mendel is the father of genetics. He studied the inheritance of traits in pea plants.
• gene is a unit of heredity, which is transferred from a parent to an offspring. It specifies trait
• hybridization is the process of interbreeding individuals of two different species to produce offspring with characteristics of both. A hybrid would therefore carry two different alleles of the same gene
• alleles is different forms of the same gene, can be dominant or recessive. It specifies what form the gene takes
• Parental generation is the generation of parents of a species.
• F1 generation is the first generation of offspring produced by a set of parents. The F in F1 stands for filial, so F1 means first filial generation
• Phenotype is the physical expression of a characteristic that results from the interaction between genes and environment, it is also the visible expressed tarit
• Genotype is the genetic makeup of an organism; it refers to the specific combination of alleles present at a particular locus on a chromosome
• dominant trait is the trait that are expressed more often and observed more commonly in the population
• recessive trait is a character expressed by a recessive gene, whose expression is suppressed by the dominant one
• Inheritance is the acquiring of genetic characteristics or traits from parents by their offspring.
• law of segregation states that alleles segregate randomly into gametes: When gametes are formed, each allele of one parent segregates randomly into the gametes, such that half of the parent's gametes carry each allele.
• When an organism has identical alleles for a particular gene, it is said to be homozygous
• When an organism has one of each allele, we call it heterozygous
• homozygous dominant and heterozygous both result in the dominant phenotype
• only homozygous recessive results in the recessive phenotype being expressed
• When one trait is being studied we use monohybrid cross
• When two traits are being studied, we use dihybrid cross
• the phenotypic distribution for a dihybrid cross will always be 9:3:3:1, where 9 represents the proportion that will exhibit the dominant phenotype for both traits, 3 represents the proportion that will show dominant for one and recessive for other, the other 3 is the reverse situation , and the 1 is for the ones that will be recessive for both
• incomplete dominance is when the phenotype of the heterozygote is intermediate between the phenotypes of the homozygous parents. In short, the dominant allele is not completely expressed when the recessive allele is around. One allele is not completely dominant with the other
• Codominance happens when both alleles are expressed. Happens when all alleles are dominant
• Epistasis happens when one gene depends on another gene for it to be expressed
• Punnett square – a matrix or grid named after the

  British geneticist R. C. Punnett, who employed it

  for determining the genetic outcome of crosses
• Albinism is a recessive trait that lacks the pigment melanin in the skin, hair, and eyes
• Cystic Fibrosis is a dominant trait that is a severe disorder that affects the production of mucus in the lungs and pancreas
• Achondroplasia is a dominant trait that causes dwarfism.
• Huntington's Disease is a dominant trait that is a degenerative neurological disorder
• pleiotropy happens when one single gene starts affecting multiple

  traits of living organisms.