Genes

• Genes are used to describe the specific sequence in DNA containing the information codes for proteins.
• Gametes are the daughter cells
• Genome is the set of all genes found in a cell responsible for the characteristics of an individual
• Heterozygous is the genotypes with two different alleles
• Homozygous is the genotype with the same alleles
• Dominant Allele is the alleles that is expressed in a heterozygous condition
• Recessive Allele is the alleles that is not expressed
• Genotype is the genetic materials found in gametes
• Phenotype is the observable characteristics
• Alleles are the genes that are responsible for a certain trait or the presence of contrasting traits
• Gregor Mendel born July 20, 1822, was died January 6, 1884, 
• Gregor Mendel a botanist, teacher, and Augustinian prelate, the first person to lay the mathematical foundation of the science of genetics, in what came to be called Mendelism.
• He showed the “factors of inheritance” that is now referred to genes. According to him there exists a pair of genetic material called alleles in every organism that segregate during gamete formation namely phenotype and genotype.
• Monohybrid a single trait crosses performed by Mendel. This can also be expressed using a diagram called Punnett Square.
• Dihybrid two different traits with constructing alleles will be traced at a time.
• Unit factors in pairs – the genetic characters are controlled by unit factors that exists in pairs in individual organisms
• Dominance and recessiveness – when two unlike unit factors responsible for a single trait are present in an individual, one-unit factor is dominant to the other, which is said to be recessive.
• Segregation – during the formation of gametes, the paired unit factors segregate randomly so that each gamete receives one or the other with equal likelihood
• Independent assortment – during gamete formation, segregating pairs of unit factors are assorted independently of each other.
• Mendelian postulates

  1. Unit factors in pair
  2. Dominance and Recessiveness
  3. Segregation
  4. Independent Assortment
• Codominance when two dominant alleles are present, both alleles will be expressed when combined. In this pattern of inheritance, there is the absence of recessive allele. This usually existed in blood antigen.
• Incomplete Dominance when dominant alleles are absent, only recessive allele will combine with another recessive allele.
• Lethal Genes is a condition when a certain combination of alleles will result to death of the carrier.
• Multiple Alleles when more than two alleles exist in a certain character, the pattern of inheritance is called
• Polygenic Inheritance - Traits that are caused by the presence of more than one gene. Genes involved in polygenic inheritance are called polygenes. These traits are also referred to as continuous traits because they are observed following a continuous range or degree of expressions.
• Sex-influenced Inheritance - this refers to autosomal traits whose expression of dominance is affected by the sex of the individual. Male-pattern baldness is an example sex-influenced inheritance.
• Pleiotropy - is a condition when one gene causes several effects (multiple traits) in various organs of the body. Genes with pleiotropy effects tend to be more severe and may affect multiple systems.
• Pedigree Analysis - is a genetic family tree that shows the members of a family affected by a certain trait that is being traced. It summarizes the phenotypes of a certain traits to several generations in a family.