Week 4-5 non mendelian genetics

• Genetics


  A branch of biology concerned with the study of genes, genetic variation, and heredity in organisms
• Inheritance


  A process by which genetic information is passed on from parents to child
• Variation


  Any difference between cells, individual organisms, or groups of organisms of any species
• Gene


  A unit of heredity, a section of DNA that codes for a specific trait
• Genotype


  The genetic makeup of an organism, the combination of two alleles
• Phenotype


  The physical appearance or the physical feature or the trait of an organism
• Homozygous


  Having two identical alleles
• Heterozygous


  Having two different alleles
• Punnett square


  A graphical representation of the possible genotypes of an offspring arising from a particular cross or breeding event
• Gregor Mendel is considered the father of genetics
• Non-Mendelian inheritance


  A type of inheritance where the patterns of phenotypes do not coincide with those presented in Mendelian laws of inheritance
• Incomplete dominance


  • One allele does not completely dominate another allele, resulting in a new or third phenotype
• Incomplete dominance


  • Red snapdragon flower crossed with white snapdragon flower results in pink snapdragon flower
• Codominance


  • Both alleles are expressed equally in the phenotype of the heterozygote
• Codominance


  • Red flower crossed with white flower results in red and white flower
• Multiple alleles


  A gene that is controlled by more than two alleles
• Multiple alleles


  • Blood types A, B, AB, and O
• Sex chromosomes


  The 23rd pair of chromosomes that determines gender, with females having XX and males having XY
• Sex-linked traits


  • Inherited through the X chromosomes
• Sex-linked trait


  • Pattern baldness
• Sex determination


  If an egg is fertilized by a sperm carrying a Y chromosome, the baby will be male; if an egg is fertilized by a sperm carrying an X chromosome, the baby will be female
• 50% of children would be expected to be male and 50% female
• Sex-influenced traits


  • Phenotypes are different between males and females with the same genotype, expressed more frequently in one sex than the other
• Sex-limited traits


  • Traits can only be expressed in one sex or the other, not found on the X and Y chromosomes
• Epigenetics


  Study of how environmental factors affect gene expression.
• Mitosis


  Cell division, resulting in two daughter cells with the same number and kind of chromosomes as the parent nucleus.
• Epigenetic Inheritance


  Environmental factors influencing gene expression and being passed on to offspring.
• Germ Cells


  Receptive cells that form during gametogenesis (sperm and egg production).
• Somatic Cells


  Non-reproductive cells that replace or repair damaged tissues.
• Meiosis


  Specialized cell division in reproductive cells (sperm and egg), resulting in four daughter cells with half the number of chromosomes.
• Gregor Mendel


  Formulated the laws of heredity based on his experiment on garden plants, considered the father of genetics
• Traits


  Physical features of an individual, passed from one generation to another through genes
• Dominant traits


  Characteristics that are expressed or visible in an organism
• Recessive traits


  Characteristics that are hidden or not expressed in an organism
• Mendel's experiments show complete dominance
• Non-Mendelian patterns of inheritance

  Patterns of phenotypes that do not occur as expected in Mendelian laws of inheritance
• Incomplete dominance


  A form of inheritance where one allele for a specific trait is not completely dominant over the other allele, resulting in a blending of characteristics
• Incomplete dominance


  • Neither allele is completely dominant, the phenotype is intermediate between the two parent traits
• Using Punnett Square to understand incomplete dominance

  1. Determine genotypes of parents

  2. Write cross mapping

  3. Draw Punnett Square

  4. Fill in Punnett Square

  5. Summarize results
• Mendel did not study incomplete dominance because the pea plant does not show it