WORD REVIEWER

• Genetics


  The study of heredity in general and genes in particular
• Genetics


  • It is a central pillar in biology
  • It overlaps with agriculture, medicine, and biotechnology
• Heredity


  The natural process wherein the parents pass their physical and mental qualities to their offspring
• Chromosome


  A pair of filamentous materials that are composed of coiled strands of DNA

  
• DNA (Deoxyribonucleic acid)


  The blueprint of the body, the genetic material of living things, made up of nucleotides that consists of sugar, phosphate groups, and nitrogenous bases
• Gene


  Sections of DNA strands, the traits of an organisms are determined by the genes on the chromosomes

  
• Factor or Allele


  The pairs of gene that occupies a particular locus in the homologous pair of chromosomes

  
• Locus


  The certain site or location where alleles are found in the homologous pair of chromosomes

  
• Phenotype


  The observable characteristics of the individual; physical expression
• Phenotype


  • Skin color - fair skin
• Genotype


  The genetic information carried by a pair of alleles that determines characteristics
• Genotype


  • Skin color - Homozygous fair skin
• Dominant


  A gene whose effect is shown in the individual whether the alleles are the same or different
• Recessive


  A gene whose effect is shown in the individual only when its alleles are the same, specifically a double recessive condition (rr)
• Homozygous


  Describing an individual where the pair of genes determining the characteristics are identical
• Homozygous


  • RR, TT, rr, tt
• Heterozygous


  Describing an individual where the pair of genes determining the characteristics are dissimilar
• Heterozygous


  • Rr, Tt
• Gregor Mendel


  He discovered the fundamental laws of inheritance, he concluded that genes comes in pairs and are inherited as distinct units from each parent
• Law of Segregation


  1. Only one number of allelic pair of chromosomes or genes will end up in the gamete in the process of meiosis

  2. Meiosis - the original number of chromosomes found in every individual is reduced in half through the egg cell and sperm cell, the union of these cells resumed the original number of chromosomes (fertilization)

  
• Law of Independent Assortment

  1. Genes are assorted independently, each trait can be inherited, but not both of them will show in the physical appearance of the offspring

  2. Metaphase 1: The alignment of chromosomes in the metaphase plate

  
• Law of Dominance and Recessiveness


  Dominant traits are manifested and recessive traits are hidden unless both recessive traits are passed onto offspring
• Law of Chance Recombination


  The egg or sperm cells combine by chance during fertilization without regard to nature of hereditary units they carry
• Monohybrid Cross


  It refers to the cross of two organisms involving only one trait
• Dihybrid Cross


  It refers to the cross of two organisms involving two traits
• Punnett Square


  A graphical representation of the possible genotypes of an offspring from a particular cross

  
• Incomplete Dominance


  The subject to the combination of genes are neither dominant nor recessive (Blending of traits)

  
• Co-dominance


  The pair of dominant gene crosses or combines (both traits manifest)
• Non-disjunction


  Both member of the allelic pair does not segregate during meiosis ending up in a gamete (Results in an unusual trait)
• Sex-Linked Traits


  Genes for these traits are located only on the X chromosome (NOT on the Y chromosome), X linked alleles always show up in males whether dominant or recessive because males have only one X chromosome

  
• Recessive sex-linked disorders


  • Colorblindness - the inability to distinguish between certain colors
• Mutation


  A sudden genetic change that occurs in the base pair sequence of DNA, resulting in an individual called mutant
• Types of mutations


  • Harmful mutations - Organism less able to survive
  • Beneficial mutations - Allows organism for better survival - provides genetic variation
  • Neutral mutations - Neither harmful nor helpful to organism
• Down's Syndrome


  Trisomy 21, 47 chromosomes, extra chromosome at pair #21

  
• Turner's Syndrome


  Only 45 chromosomes, missing a sex chromosome (X), girls are affected - short, slow growth, heart problems

  
• Klinefelter's Syndrome


  An inherited disorder of males, males have an extra X chromosome and don't develop normal sexual characteristics of puberty, however, most men with Klinefelter's syndrome can live normal lives
• Having an extra set of chromosomes is fatal in animals, but in fruit, it makes them larger and harder