Chapter 1- Overview of genetics
• Genes and alleles
• DNAand RNA
• Genetic Testing
Genes and Alleles
Gene – segment of DNA(a gene codes for production of a protein)
Allele – variant of a gene
Example: Sickle-cell anemia
• Caused by mutated gene - codes for component of hemoglobin.
• An allele of the gene codes for a defective hemoglobin.
• Result is sickle-cell anemia.
• DNA = Deoxyribonucleic acid.
– 4 DNAbuilding blocks:A, T, G, C
• RNA = Ribonucleic acid. Intermediary between genes and proteins.
– 4 RNAbuilding blocks:A, U, G, C
• Long strand of DNAand proteins. Each chromosome contains many genes.
• Humans: 46 chromosomes in all cells except sperm and eggs.
– 23 from mom
– 23 from dad
• All genes in cells of a particular type of organism.
• Human genome is approximately 20,000 genes
• Corn has 30,000 genes and the worm C. elegans has 10,000
Genotype and Phenotype
Genotype – alleles an organism contains
Phenotype – how those alleles are expressed (what the organism looks like).
Ex: Flower color
PP = purple
Pp = purple
pp = white Karyotype
• Chart that displays chromo