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10 1.3 Inheritance
Question | Answer |
---|---|
Genetics | the study of inherited characteristics |
Gregor Mendel | developed the original theory of genetics. |
Pure-breeding | all individuals have the same genetic information eg red flowered plants only give rise to red flowered plants |
Dominant | the characteristic that is observed in the next generation eg 'R' for Red (dominant) |
Recessive | a characteristic that may remain hidden in the next generation eg 'r' for White (recessive) |
Alleles | variations of a gene eg for colour 'R' for Red (dominant) and 'r' for White (recessive) |
Homozygous | having 2 alleles exactly the SAME either RR or rr |
Heterozygous | having 2 different alleles MIXED either rR or Rr |
Punnett square | a method of representing possible outcomes from breeding |
Genotype | represented by the alleles eg RR, rr, or rR (ie its genes) |
Phenotype | the characteristic - flower colour or face (sort of rhymes at the first letter) |
Incomplete dominance | some genes have alleles that neither dominate or are recessive, they blend, which makes the offspring different from both of its parents. Red + White = Pink |
Sex-linked genes | some genes are only found on the X and Y genes - colour blindness is only found on the X chromosome. Haemophilia is also sex linked. |
Mutation | mistakes do occur in the copying of DNA either due to chance, UV radiation, nuclear radiation, nicotine or many other causes. If this mistake occurs in the egg or the sperm then the mutation may be passed onto the next generation. |
Co-Dominance | Both alleles are expressed equally. Red + White = Red and White Spots |