GEN BIO (TERMS IN GENETICS)

• Genetics

  • study of heredity in general and genes in particular
  • has a wide scope
• Heredity

  • transfer of genes from generation to generation
  • a pillar of genetics
• HIERARCHY OF A CHROMOSOME

  
  

  CHROMOSOMES are made up of SISTER CHROMATIDS which are further made up of CHROMATIDS. When stretched, they are called CHROMATIN, and when further stretched are DNA. 3 pairs are called GENE.
• Allele or Factor

  • the specific trait
• Locus

  • location of a certain allele or factor
  • LOCI is the plural form
• CHROMOSOMES IN HUMANS

  
  

  Humans have 46 chromosomes and 23 pairs of chromosomes: 22 pairs of AUTOSOMES and 1 pair of SEX CHROMOSOME
• SEX CHROMOSOME

  • determines whether a human is female or male
  • only enhances the autosome
  • XX for females and XY for males
• SEX CHROMOSOME

  • all egg cells contain "X" while sperm cells contain either "X" or "Y"
  • the sperm cell determines the gender
• AMOUNT OF SPERM RELEASED IN AN EJACULATION

  
  

  In 1 ejaculation, 60-72 million sperm cells are released.
• Phenotype

  • physical characteristics
  • i.e. skin color - brown, eye shape - round
• Genotype

  • genetic information in the DNA
  • i.e. skin color - FF, eye shape - Rr
• Dominant

  • effect shown on an individual regardless if the allele is same or different
  • written in capital letters: RR, Tt
• Recessive

  • effect only shown if two alleles are the same
  • written in small letters: rr, tt
• Homozygous

  • the pair of genes are either all dominant or all recessive
  • i.e. RR, TT, rr, tt
• Heterozygous

  • the pair of genes are dissimilar
  • i.e. Rr, Tt
• Reading Genes

  • In reading genes, the dominant trait takes the priority
  • i.e. RR - Homozygous Dominant Round, tt - Homozygous Recessive Short, Tt - Heterozygous Dominant Tall
• IDENTIFY THE GENOTYPE AND PHENOTYPE

  (RRTt)

  • R - round, r - wrinkled
  • T - tall, t- short

  G: Homozygous Dominant Round, Heterozygous Dominant Tall

  P: round, tall, short
• IDENTIFY THE GENOTYPE AND PHENOTYPE

  (TtWw)

  • T - tall, t - short
  • W - pale, w - tan

  G: Heterozygous Dominant Tall, Dominant Pale

  P: tall, short, pale, tan