HDFS 230 1st Edition Lecture 5Chapter 2: Genes• DNAo Contains chemical instructions for cells to make various proteinso Biological roadmap for human developmento Chromosome= molecule of DNA-Autosomes-22 pairs-Sex chromosomes – 1 pair•XX-female•XY- maleo Gene: specific sections of a chromosome that carry chemical instructionso Organized into 4 pairs-(AT, TA, CG, Gc)-3 billiono Most traits are Polygenic; affected by many genes-Height is an additive trait involving more than 100 genes-Multifactorial: influenced by many factors o Sex cellsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Gametes: • Reproductive cells (sperm and ova)• Each gamete consists of 23 chromosomes-Meiosis • Reductional division creating gameteso Genes take different forms known as Alleles-Vary slightly in their codes from one person to another• Homozygous: same e.g. AA or aa• Heterozygous: different e.g. Aao Dominant recessive-1 dominant copy-> dominant gene expressedo-Incomplete Dominance: effect of recessive genes can sometimes be noticed • Hazel eyeso Recessive-recessive-Inherit two copies of recessive gene: recessive gene expressed• Odds are one ¼o Carrier-Genotype includes a gene not expressed in the phenotype• Unexpressed gene occurs in half of the carriers gameteso Sex-linked inheritance: for males, recessive gene on X chrom. Can be expressed -Color blindness, hemophilia• Gene environment interactionso Environment can affect the expression of genes. o Without genes no behavior would existo Without environment, no genes could be expressed• Range of reactiono Each persons unique genetically determined response to the environment• Genetic-environmental correlations: Gene influence the environments to which we are exposedo Early in life:-Passive correlation: parents provide environments influenced by their own heredity-Evocative correlation: children evoke responses influenced by their heredityo Later in life: -Active (niche-picking) actively choose environments that complement our