* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Yr 10 inheritance notes
Genetic engineering wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
History of genetic engineering wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Genome evolution wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Genomic imprinting wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Hybrid (biology) wikipedia , lookup
Gene therapy wikipedia , lookup
Genome (book) wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Gene desert wikipedia , lookup
The Selfish Gene wikipedia , lookup
Gene expression profiling wikipedia , lookup
Gene nomenclature wikipedia , lookup
Gene expression programming wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Microevolution wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Designer baby wikipedia , lookup
Rules to remember: In an intermediate inheritance If both parents are pure(have identical genes) then they’ll produce one genotype in F1. B/B B or B B/W W/W W or W B/W One B/W B/W genotype If one parent is pure and the other is hybrid(have 2 different genes), then two genotypes are produced. B/B B or B B/B B/W B or W B/B First genotype B/W B/W second genotype If both parents are hybrids (have 2 different genes), then three genotypes are produced. B/W B or W B/B First genotype B/W B or W W/B B/W second genotype W/W third genotype D:\769876481.doc Yr10 dominant/recessive inheritance – New Generations We have looked at both genes having an effect. We say that both are being expressed. We called that intermediate inheritance. Now, when only one gene is being expressed at the expense of the other, we call that dominant inheritance. The dominant gene ‘hides’ the effect of the other gene for that characteristic. It is stronger than the other gene. We call a ‘strong’ gene a dominant gene. We call a ‘weak’ gene a recessive gene. A recessive gene is one that recede for a generation only to reappear in the next generation. We refer to a dominant gene with a capital letter e.g. T We refer to a recessive gene with a lower case letter e.g. t When predicting the kind of offsprings we might have, we use the punnet square. The shaded area tell us about the genotype, and hence the phenotype of these offsprings. E.g. Sex Cells T t T(dominant) TT Tt t(ecessive) Tt tt In this case if T were to stand for dominant characteristic for tallness, and t for shortness, we find that the ratio of different characteristics is as follows: ¼ TT ½ Tt ¼ tt (This is called genotypic ratio). ¼ pure tall ½ hybrid tall ¼ pure short (This is called phenotypic ratio). ¾ tall D:\769876481.doc and ¼ short An easy way to predict the kinds of offsprings resulting from two parents mating is to use the punnet square. Rules for predicting outcomes of dominant gene inheritance. 1. When a pure dominant parent mates with a pure dominant parent: 1 genotype is produced; 1 phenotype is produced. B B Phenotypic ratio: all pure black. B/B B/B B Genotypic ratio: all B/B. B/B B/B B 2. When a pure dominant parent mates with a pure recessive parent: 1 genotype is produced; 1 phenotype is produced. B B Phenotypic ratio: all hybrid black. B/b B/b b Genotypic ratio: all B/b. B/b B/b b 3. When a pure recessive parent mates with a pure recessive parent: 1 genotype is produced; 1 phenotype is produced. b b Phenotypic ratio: all white. b/b b/b b Genotypic ratio: all b/b. b/b b/b b 4. When a hybrid parent mates with another hybrid parent: 3 genotypes are produced; 2 phenotypes are produced. B b Phenotypic ratio: ¾ black; ¼ white B/B B/b B Genotypic ratio: ¼ B/B; ½ B/b; ¼ b/b B/b b/b b 5. When a hybrid parent mates with a pure dominant parent: 2 genotypes are produced; 1 phenotype is produced. B B Phenotypic ratio: all black. B/B B/B B Genotypic ratio: ½ B/B; ½ B/b B/b B/b b 6. When a hybrid parent mates with a pure recessive parent: 2 genotypes are produced; 2 phenotypes are produced. b b Phenotypic ratio: ½ black; ½ white. B/b B/b B Genotypic ratio: ½ B/b; ½ b/b b/b b/b b D:\769876481.doc