GENE MUTATION

• Phenotype - the physical expression of a gene.

  • EX: Skin complexion, eye color, height
• Genotype - the genetic makeup of an organism, including the alleles it carries

  • The total sum of genes transferred from parents to offspring
• Genotype is represented by letters: BB, Bb, bb
• Alleles - is an alternative form or version of a gene, from two parents.

  • These are expressed in genes
• Homozygous dominant allele is when both alleles are dominant and the phenotype is expressed

  • "Homo" - means 'same', so they are expressed in both big letters (BB) because same alleles are dominant
• Heterozygous dominant - A genotype that is dominant over the recessive allele.

  • "Hetero" - means 'different' so alleles are expressed in different letters (Bb) - 1 dominant and 1 recessive
• Recessive - A trait that cannot be seen in an offspring because it is overshadowed by dominant allele

  • Expressed in both small letters (bb)
• When brown eyes are dominant compared to black eye, the black eye is recessive
• proteins - active cell machinery
• Amino acids - building block of proteins
• Punnet square - diagram used to predict the genotypes of cross breeding
• Punnett square was named after Reginald C. Punnett
• If brown eyes is homozygous dominant the offspring will have 100% brown eyes
• In karyotype, chromosome 23 is where we can determine the offspring's sex
• Most of the population's sex is female (XX)

  • because males have only one X chromosome (XY)
• Locus - it is where the alleles designated.

  • The actual location of the gene on a region of a chromosome
• DNA's complementary bases are A, T, C, and G.

  • Adenine
  • Thymine
  • Cytosine
  • Guanine
• Mutation - any change that occurs to an organism’s DNA sequence.
• RNA is known for the presence of Uracil (U) instead of Thymine (T)
• Mitosis - a type of asexual reproduction in which a single cell divides to form two identical daughter cells

  • "Asexual" - without gametes
• Meiosis - a type of sexual reproduction, where sex cells are produced from a single parent cell
• In humans, MEIOSIS reduces the number of chromosomes (n), while MITOSIS retain the number of chromosomes (2n)
• Meiosis produces 4 haploid cells with variation
• Codominance - all alleles are expressed in the phenotype.

  • EX: Tan + Black = Tan+Black (diploid) = Tan+Black (haploid)
  • As we can see, tan and black are expressed
• Incomplete dominance - no two alleles are expressed in the phenotype

  • EX: Red rose + White rose = Pink rose
• Dominance is the expressed trait and the recessive trait cannot be seen because it is overshadowed by the dominant trait
• Monosomy - the presence of a single chromosome in a pair.
• Trisomy - an extra copy of a chromosome, resulting in a person having three copies of a chromosome
• Down syndrome - trisomy 21
• Turner Syndrome - monosomy X
• Klinefelter's Syndrome - XXY
• CHROMOSOMAL ANOMALIES

  Earlobes: can be FREE or ATTACHED
• CHROMOSOMAL ANOMALIES

  Widow's peak / Straight hairline
• CHROMOSOMAL ANOMALIES

  Tongue roll
• CHROMOSOMAL ANOMALIES

  Mid digital hair - hair on fingers
• CHROMOSOMAL ANOMALIES

  F_reckles
• CHROMOSOMAL ANOMALIES

  D_imples
• CHROMOSOMAL ANOMALIES

  Right over left / Left over right
• CHROMOSOMAL ANOMALIES

  PTC Taster - can taste bitter

  PTC non-taster - cannot taste bitter
• PTC - Phenylthiocarbamide (the bitter organic compound)