lecture 1 - introduction to genetics Flashcards
why does genetics matter
genetics is the study of inheritance and variation in traits
transmission genetics
transfer of genetic information from parents to offspring
molecular genetics
DNA and the genome (franklin, watson, and crick
genome
an organisms full DNA sequence, or the DNA or RNA sequence of a virus
genes
specific base sequences passing traits from parents to offspring. genetic material in cells is organized into chromosomes
prokaryotes
dont have a nucleus, or membrane bound organelles, generally have one circular chromosome
eukaryotes
usually have a nucleus with chromosomes and DNA in organelles
chromosomes
- composed of DNA and protein
- most prokaryotes have single, usually circular chromosomes
- in eukaryotes, chromosomes have linear structures
- chromosomes differ in size and morphology
- each has a constriction called a centromere
chromosomal DNA
- DNA packaged efficiently in a chromosome, coiled around molecular spools: nucleosomes
- each nucleosome is composed of either proteins: histones
- DNA plus associating nucleosomes are called chromatin
the central dogma
transfer of instructions stored in DNA (genotype) into proteins that perform physical action and make physical form (phenotype)
population genetics
change in genetic information among individuals over generations
sources of variation in DNA
- mutations: heritable changes in genetic material that may be spontaneous or induced. when not repaired, they fix in the genome and are passed to the next generation
- recombination: exchange of genetic material is produced by enzymes that cut and rejoin DNA molecules
- selection: favoring particular gene combinations in a given environment
- epigenetic: changes in phenotype in the absence of any underlying change in the DNA sequence
genetic maps
sites of genes (loci) on chromosomes, and genetic distances between them calculated from recombination in experimental crosses. they show whether genes with related functions are on the same chromosomes
