Meiosis/Genetics

1. Meiosis/Genetics Topic 4

2. Stages of Meiosis

3. Meiosis Stage 2

4. Genes and Chromosomes • Terminology: • Genotype – genetic constitution of a gene/org • Phenotype – physical expression of a gene • Dominant allele – form of the gene that is expressed even when only 1 is present • Recessive allele – form of the gene that is only expressed when both alleles are recessive

5. Terminology cont’d • Codominant allele – when two two forms of a gene are both expressed when paired together • Locus – the location of a gene/allele on a chromosome • Homozygous – when both alleles of a gene are the same (ex. aa, AA) • Heterozygous – when both alleles of a gene

6. Terminology cont’d • Carrier – an individual of heterozygous make-up that carriers, and therefore can pass on, a disease causing allele but doesn’t express that trait • Test cross – when an individual of known phenotype but unknown genotype (AA or Aa) is crossed with a homozygous recessive individual in order to determine its genetic make-up.

7. Mendelian Genetics – Monohybrid Cross Classical Punett's Square is a way to determine ways traits can segregate parental P cross F1 cross testcross: mating F1 generation to the parental (usually recessive) strain

8. Some genes have more than two alleles- Blood surface antigens

9. Blood type also and ex. Of Codominance

10. Sex-linkage basics

11. Sex-linkage notes page

12. Pedigree basics

13. Pedigrees and pedigree analysis

14. Sex-linked Pedigree