Bio 11&13&14

Front 1

genetics

Back 1

scientific study of heredity

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fertilization

Back 2

process in sexual reproduction in which male and female reproductive cells join to form a new cell

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true-breeding

Back 3

term used to describe organisms that produce offspring identical to themselves if allowed to Self-pollinate

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trait

Back 4

specific characteristic that varies from one individual to another

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hybrid

Back 5

offspring of crosses between parents with different traits

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gene

Back 6

sequence of DNA that codes for a protein and thus determines a trait

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allele

Back 7

one of a number of different forms of a gene

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segregation

Back 8

separation of alleles during gamete formation

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gamete

Back 9

specialized cell involved in sexual reproduction

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probability

Back 10

likelihood that a particular event will occur

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Punnett square

Back 11

diagram showing the gene combinations that might result from a genetic cross

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homozygous

Back 12

term used to refer to an organism that has two identical alleles for a particular trait

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heterozygous

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term used to refer to an organism that has two different alleles for the same trait

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phenotype

Back 14

physical characteristics of an organism

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genotype

Back 15

genetic makeup of an organism

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independent assortment

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independent segregation of genes during the formation of gametes

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incomplete dominance

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situation in which one allele is not completely dominant over another

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codominance

Back 18

situation in which both alleles of a gene contribute to the phenotype of the organism

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multiple alleles

Back 19

three or more alleles of the same gene

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polygenic trait

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trait controlled by two or more genes

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homologous

Back 21

term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent

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diploid

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term used to refer to a cell that contains both sets of homologous chromosomes

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haploid

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term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes

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tetrad

Back 24

structure containing 4 chromatids that forms during meiosis

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meiosis

Back 25

process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

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crossing-over

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process in which homologous chromosomes exchange portions of their chromatids during meiosis

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gene map

Back 27

diagram showing the relative locations of each known gene on a particular chromosome

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selective breeding

Back 28

method of breeding that allows only those individual organisms with desired characteristics to produce the next generation

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hybridization

Back 29

breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms

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inbreeding

Back 30

continued breeding of individuals with similar characteristics to maintain the desired characteristics of a line of organisms

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genetic engineering

Back 31

process of making changes in the DNA code of living organisms

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restriction enzyme

Back 32

enzyme that cuts DNA at a specific sequence of nucleotides

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gel electrophoresis

Back 33

procedure used to separate and analyze DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel

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recombinant DNA

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DNA produced by combining DNA from different sources

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polymerase chain reaction (PCR)

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technique that allows molecular biologists to make many copies of a particular gene

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plasmid

Back 36

small circular piece of DNA

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genetic marker

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gene that makes it possible to distinguish bacteria that carry a plasmid with foreign DNA from those that don't

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transgenic

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term used to refer to an organism that contains genes from other organisms

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clone

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member of a population of genetically identical cells produced from a single cell

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karyotype

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photograph of chromosomes grouped in order in pairs

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sex chromosome

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one of two chromosomes that determine an individual's sex; females have two X chromosomes; males have one X chromosome and one Y chromosome

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autosome

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chromosome that is not a sex chromosome

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pedigree

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chart that shows the relationships within a family

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sex-linked gene

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gene located on the X or Y chromosome

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nondisjunction

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error in meiosis in which homologous chromosomes fail to separate

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DNA fingerprinting

Back 46

analysis of sections of DNA that have little or no known function, but vary widely from one individual to another, in order to identify individuals