Chapter 14 Mendel and the Gene Idea – Flashcards
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Blending hypothesis
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the idea that genetic material contributed by the two parents mixes in a manner analogous to the way blue and yellow paints blend to make green
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gene idea
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parents pass on discrete heritable units -- genes -- that retain their separate identities in offspring
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Gregor Mendel
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abby garden, monk, documented a particulate mechanism of inheritance; discovered the basic principles of heredity by breeding garden peas in carefully planned experiments
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character
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name for a heritable feature, such as flower color, that varies among individuals
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trait
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each variant for a specific characteristic that varies from one individual to another, white vs purple
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true-breeding
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term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate
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hybridization
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(genetics) the act of mixing different species or varieties of animals or plants and thus to produce hybrids
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p generation
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true-breeding parents
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F1 generation
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the hybrid offspring of the p generation
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F2 generation
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the offspring of the F1 generation
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allele
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one of many alternate forms of a gene that can have the same locus on homologous chromosomes and are responsible for alternative traits. for each character, an organism inherits 2 of these for each character
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dominant
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an allele whose trait always shows up in the organism when the allele is present
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recessive allele
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an allele that is masked when a dominant allele is present
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law of segregation
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members of a pair of homologous chromosomes separate during the formation of gametes and are distributed to different gametes so that every gamete receives only one member of the pair (allele)
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phenotype
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what an organism looks like as a consequence of its genotype
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genotype
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the particular alleles at specified loci present in an organism; genetic makeup
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homozygous
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having identical alleles at corresponding chromosomal loci
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heterozygous
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having dissimilar alleles at corresponding chromosomal loci
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testcross
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mating of an individual of unknown genotype but dominant phenotype with a homozygous recessive individual. most efficient if you cross with an individual expressing the recessive trait
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monohybrids
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heterozygous for one character
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dihybrids
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individuals heterozygous for two characters`
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incomplete dominance
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one allele is not completely dominant over the other allele, red+white=pink
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codominance
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situation in which both alleles of a gene contribute to the phenotype of the organism; red+white=red and white stripes
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epistasis
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A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.
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pleiotropy
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A single gene having multiple effects on an individuals phenotype
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quantitative characters
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A heritable feature in a population that varies continuously as a result of environmental influences and the additive effect of two or more genes (polygenic inheritance).
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polygenic inheritance
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process by which several genes interact to produce a certain trait; responsible for most important traits ex skin tone
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norm of reaction
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The range of phenotypes produced by a single genotype, due to environmental influences.
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multifactorial
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involving or depending on several factors or causes for genes it could be genetics and environment
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pedigree
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a diagram that shows the occurrence of a genetic trait in several generations of a family
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amniocentesis
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A technique of prenatal diagnosis in which amniotic fluid, obtained by aspiration from a needle inserted into the uterus, is analyzed to detect certain genetic and congenital defects in the fetus.
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choronic villus sampling
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placental tissue test for prenatal diagnosis of potential genetic defects done btw weeks 8-12
