Somatic mutations: mutations in cells other than sex cell )soma=body); can't be inherited because they do not affect sex cell
Chromosomes appear in homologous pairs, one set originating from the sex cell of the female parent and the other set originating from the sex cell of the male parent
The % of crossovers is proportional to the distance between 2 genes on a chromosomes- so % crossover is the number of crossovers between 2 genes per 100 opportunities in meiosis
a chromosome map can be made that indicates the positions along the chromosome of genes that code for certain characteristics
Methods have been developed to insert a DNA fragment of interest (e.g. a piece of human DNA) into the DNA of a vector (carrier), resulting in a recombinent DNA molecule or molecular clone. A vector is a self-replicating DNA molecule (e.g. a plasmid, which is a circular piece of DNA found in beacteria)
Co-Dominance: intermediate (red+ white= pink); follow Mendal's Law
Polygenic inheritance: a single trait[¯S¼x] is controlled by multiple genes
Nucleotides = A, T, C, G (A=T; C=G); double helix is held by weak hydrogen bond
A gene is a sequence of nucleotide pairs along a DNA molecule which codes for an RNA or polypeptide product.
1. structural genes, which code for functional protein (enzyme, hormone, antibody, etc)
2. regulatory genes, whcih control the activity of other genes
The differentiation of cells into different types is due to the genetic switch
1. In gene induction, genes that are induced are normally switched off. The inducer is the substrate
2. In gene repression, genes that are repressible are normally switched on. The presence of high levels of the end-product of a metabolic process activated the repressor molecule
stop codon: UAA, UGA, UAG
Restriction enzymes are enzymes whcih cut DNA at specific point
The frequency of alleles for any character will remain unchanged in a population through any number of generations unless this frequency is altered by some outside influence
Conditions required: large population, random mating, no emigration or immigration: no gene flow, no selection pressure, no mutation
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geocities.com/hk)