Mid Genetics Completed

• In the 1860 s, he introduced a new theory on inheritance based on his experimental work with pea plants.

  Gregor Johann Mendel
• He believed that heredity is the result of discrete units of inheritance, and even single unit or gene was dependent in i its actions in an individual’s genome

  Gregor Johann Mendel
• Father of Genetics


  Gregor Johann Mendel
• Inheritance of a trait depends on the passing-on of units/genes.
• Mendel called the visible form the

  dominant trait
• Mendel called the hidden form the

  recessive trait
• The alternate forms of genes are called the

  alleles.
• If the two genes are different then the individual is called

  heterozygous
• The pair of alleles in an individual that are responsible for the expression of a certain traits is termed as

  genotype
• The observable characteristic of individual is called

  phenotype
• When mating occurs between two organisms of different traits, each offspring exhibits the trait one parent only.

  LAW OF DOMINANCE
• Both alleles of a given gene are expressed equally in each offspring.

  LAW OF SEGREGATION
• 3 Phenotypic Ratios


  3:1 Ratio

  1:1 Ratio

  uniform progeny
• A phenotypic ratio results from the mating of a

  homozygous parent and a heterozygous parent.

  1:1 Ratio
• During the formation of the gamete, the alleles of one trait will segregate independently of another trait. Therefore, the inheritance of genes responsible for the expression of color and shape of the seeds were not dependent on each other.

  LAW OF INDEPENDENT ASSORTMENT
• It is a convenient way of organizing all the combinations of characteristics

  BRANCH DIAGRAM
• is a mathematical measure of likelihood or a likelihood that a particular event will occur

  Probability
• It is applied when considering two mutually exclusive outcomes that can result from more than one pathway

  SUM RULE
• It uses probability to detect differences between Expected and Observe

  Chi Square test
• both traits are expressed but the traits are blended together rather than occurring in discrete patches

  Incomplete Dominance
• more than two alleles are present within a group of organisms

  MULTIPLE ALLELISM or Allelic Series
• variability in the degree to which the phenotype is expressed.


  Expressivity
• it is one that causes death at a near stage of development- often before birth-and so some genotypes may not appear among the progenies.

  lethal allele
• are specialized cells - eggs

  Gametes
• the genotype does not

  always produce the expected phenotype, a phenomenon


  incomplete penetrance.
• the condition of having extra fingers and toes

  polydactyly
• genes exhibit independent assortment but do not act independently in their phenotypic expression; instead, the effects of genes at one locus depend on the presence of genes at other loci

  GENE INTERACTION
• Sometimes the effect of gene interaction is that one gene masks (hides) the

  effect of another gene at a different locus, a phenomenon known as

  epistasis
• environmental factors alone can

  produce a phenotype that is the same as the phenotype produced by a

  genotype; this phenotype is called


  phenocopy
• If both members of a twin pair have a trait, the twins

  are said to be

  concordant
• if only one member of the pair has the trait, the

  twins are said to be

  discordant
• used to analyze the pattern of inheritance of a particular trait throughout a family. It shows the presence or absence of a trait as it relates to the relationship among parents, offsprings, and siblings

  Pedigrees
• The 22 chromosome pairs other than the XX (female) or XY (male) sex chromosomes


  Autosomal chromosomes
• males only have one X chromosome and one allele of any X-linked gene.

  hemizygous
• usually appear equally in both sexes and do not skip generations. When an affected son of non-founding parents has an affected father, the disease must be?

  Autosomal dominant traits
• appear more frequently in males than in females. Half of their sons will have the trait and half of their daughters will be unaffected carriers

  X-linked recessive traits
• appear only in males and are passed from father to all sons


  Y-linked traits
• Is the study of biologically variation and traits.

  Genetics
• holds that structures such as body organs are not initially present in the early embryo but instead are formed de novo (anew)

  Epigenesis
• all organisms are composed of basic units called

  cells, which are derived from similar preexisting

  structures.

  cell theory