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Genetics Lesson 1. Definitions . Allele Gene Homozygous Heterozygous Dominant Recessive Co-dominant Diploid Haploid Karyotype Chromosome Homologous Locus Genotype Phenotype. Genetic Cross Diagrams. Male or Female What are the chances of having a baby boy?
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Definitions • Allele • Gene • Homozygous • Heterozygous • Dominant • Recessive • Co-dominant • Diploid • Haploid • Karyotype • Chromosome • Homologous • Locus • Genotype • Phenotype
Genetic Cross Diagrams • Male or Female • What are the chances of having a baby boy? • Show the genotypic and phenotypic frequencies
Genetic Cross Diagrams • Huntington’s Disease • A normal male reproduces with a female sufferer • What is the F1’ filial generation? • Provide the genotypic and phenotypic ratios
Monohybrid Inheritance – inheritance of a single gene • Pure breeding = HOMOZYGOUS throughout • Pea Flowers – red, white and pink • Pure bred red with Pure bred white • F1 generation results = • F2 generation results when crossed with pure bred red
Cystic Fibrosis • Cross a Carrier female with a normal male • What are the chances of having a male carrier?
http://www.newscientist.com/article/dn10013-cystic-fibrosis-gene-protects-against-tuberculosis.htmlhttp://www.newscientist.com/article/dn10013-cystic-fibrosis-gene-protects-against-tuberculosis.html • Why does Cystic Fibrosis still exist? • Why are white people more likely to suffer from Cystic Fibrosis?
Sickle cell Anaemia • Co-dominance • Cross a couple both with the sickle cell trait (heterozygotes)
Why would the sickle cell haemoglobin have a different structure to a normal haemoglobin?
X and Y chromosomes Does this set of chromosomes come from a male or female? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 XY What kind of sex chromosomes are there in this person’s sex cells?
Diseases • The gene for Haemophilia is recessive but if you are a carrier you can have slight problems in clotting. • The Queen is a carrier (Hh) • What is her genotype? • If she mates with another carrier what are the ratio of genotypes and phenotypes produced.
Sex Determination • 2 months • SRY – sex determining region of Y • Wolffian Duct • Mullerian Duct
Duchenne Muscular Dystrophy • Mutation in the dystrophin gene • Weakness • Issues with walking and mobility • Fibrosis of tendons
Sex Linkage • I am red colour blind. • If I were to mate with a normal sighted person (not a carrier) • What are the chances of my children being colour blind? • What are the chances of my Grandchildren being colour blind if they mate with a colour blind person? • Show the genotype and phenotype ratios for each answer
Co Dominance • Cat Coat • Brown • Ginger • Tortoiseshell
Page 124 Question 3 • Siamese cats • Tyrosinase • Why are all kittens born the same colour then develop these markings?
Alleles • Pleiotropy • Polygenic Inheritance • Multiple Alleles
Blood Groups • ABO and Rhesus Groups • Rhesus = Antigen D on the surface of Red Blood Cell • How can the Rhesus type cause an issue during childbirth?
ABO Inheritance • A mother who is blood group A and a father who is blood group B have two children • One is group O and the other AB • What are the genotypes of the parents, use a genetic diagram to answer your question • A woman of group A has a baby with group O. She does not know who the father is. A boyfriend had group B, her husband group AB. Who was the father?
Multiple alleles and Dominance hierarchy • Coat Colour • Agouti C A • Chincilla C Ch • Himalayan C H • Albion C a