Genetics Notes

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‭Genetics‬
‭●‬ ‭Up‬‭until‬‭the‬‭mid-1800s,‬‭people‬‭believed‬‭in‬‭the‬‭blending‬‭theory‬
‭○‬ ‭This‬‭is‬‭the‬‭theory‬‭that‬‭offspring‬‭have‬‭a‬‭blend,‬‭or‬‭mix,‬‭of‬‭the‬‭characteristics‬‭of‬
t‭ heir‬‭parents‬
‭●‬ ‭Gregor‬‭Mendel‬‭(1842)‬
‭○‬ ‭Austrian‬‭Monk‬‭who‬‭studied‬‭peas‬
‭○‬ ‭Father‬‭of‬‭modern-day‬‭genetics‬




‭●‬ ‭Mendelian‬‭genetics‬
‭○‬ ‭One‬‭characteristic‬‭always‬‭showed‬‭up‬‭in‬‭the‬‭first-generation‬
‭○‬ ‭Dominant‬‭and‬‭recessive‬
‭■‬ ‭A‬‭dominant‬‭gene‬‭produces‬‭proteins‬‭that‬‭can‬‭mask‬‭the‬‭recessive‬‭gene‬
‭proteins‬
‭■‬ ‭Recessive‬‭genes‬‭are‬‭the‬‭ones‬‭that‬‭are‬‭being‬‭masked‬
‭○‬ ‭The‬‭principle‬‭of‬‭segregation‬‭states‬‭that‬‭genes‬‭or‬‭alleles‬‭will‬‭separate‬‭during‬
‭meiosis‬
‭○‬ ‭The‬‭principle‬‭of‬‭independent‬‭assortment‬‭states‬‭that‬‭alleles‬‭or‬‭genees‬‭on‬
‭different‬‭chromosomes‬‭will‬‭separate‬‭independently‬‭of‬‭each‬‭other‬‭during‬
‭meiosis‬
●‭ ‬ ‭Self-pollination‬‭-‬‭plants‬‭can‬‭pollinate‬‭themselves‬
‭●‬ ‭Cross-pollination‬‭-‬‭pollinate‬‭one‬‭plant‬‭with‬‭another‬
‭●‬ ‭Molecular‬‭genetics‬
‭○‬ ‭Study‬‭of‬‭the‬‭structure‬‭and‬‭function‬‭of‬‭chromosomes‬‭and‬‭genes‬
‭○‬ ‭Heredity‬‭-‬‭transmission‬‭of‬‭traits‬‭from‬‭parent‬‭to‬‭offspring‬
‭○‬ ‭Chromosomes‬‭-‬‭tightly‬‭packed‬‭coils‬‭of‬‭DNA‬‭that‬‭have‬‭genes‬‭that‬‭code‬‭for‬
‭proteins‬
‭○‬ ‭Genes‬‭-‬‭segments‬‭of‬‭DNA‬‭that‬‭code‬‭for‬‭proteins‬
‭○‬ ‭Traits‬‭-‬‭characteristics‬‭produced‬‭by‬‭genes‬
‭●‬ ‭Alleles‬
‭○‬ ‭Alternate‬‭forms‬‭of‬‭the‬‭same‬‭gene‬‭are‬‭found‬‭on‬‭homologous‬‭chromosomes‬
‭●‬ ‭Phenotype‬‭-‬‭outward‬‭appearance‬‭produced‬‭by‬‭a‬‭set‬‭of‬‭genes‬

, ‭73‬


●‭ ‬ ‭ enotype‬‭-‬‭gene‬‭type,‬‭actual‬‭gene‬‭order‬
G
‭●‬ ‭Monohybrid‬‭cross‬
‭○‬ ‭Cross‬‭involving‬‭only‬‭one‬‭trait‬‭or‬‭characteristic‬
‭●‬ ‭Homozygous‬‭(two‬‭dominant‬‭or‬‭two‬‭recessive)‬
‭○‬ ‭Homozygous‬‭dom.‬‭X‬‭homozygous‬‭rec.‬
‭■‬ ‭Two‬‭dominant‬‭alleles‬‭vs‬‭two‬‭recessive‬‭alleles‬
‭○‬ ‭Heterozygous‬‭x‬‭homozygous‬‭rec‬
‭■‬ ‭Heterozygous‬‭(one‬‭of‬‭each)‬
‭○‬ ‭Heterozygous‬‭x‬‭heterozygous‬
‭●‬ ‭Test‬‭cross‬
‭○‬ ‭Used‬‭to‬‭find‬‭the‬‭genotype‬‭of‬‭an‬‭unknown‬‭dominant‬‭organism‬
‭○‬ ‭Cross‬‭it‬‭with‬‭a‬‭homozygous‬‭recessive‬‭individual‬
‭○‬ ‭50%‬‭dominance‬‭→‬‭heterozygous‬
‭○‬ ‭100%‬‭dominance‬‭→‬‭homozygous‬‭dominant‬
‭●‬ ‭Incomplete‬‭dominance‬‭(partial‬‭dominance)‬
‭○‬ ‭Neither‬‭allele‬‭is‬‭completely‬‭dominant‬‭to‬‭the‬‭other‬
‭○‬ ‭Ex.‬
‭■‬ ‭Red‬‭is‬‭dominant‬‭to‬‭white,‬‭but‬‭in‬‭carnations,‬‭red‬‭is‬‭incomplete‬
‭dominant‬




‭●‬ ‭Codominance‬
‭○‬ ‭When‬‭two‬‭alleles‬‭are‬‭equally‬‭dominant‬
‭○‬ ‭Ex.‬
‭■‬ ‭Cow‬‭color/cat‬‭color‬