Genetics
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Created by:
elenathewalrus on March 2, 2012
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52 terms
Terms | Definitions |
|---|---|
 Mendel | austrian monk, 1822-1884, lived and worked at monastery, cross bred pea plants with single and multiple trait crosses, identified idea of dominant and recessive traits |
| segregation | alleles separate when gametes form |
| traits | specific characteristics from an organism, passed from one generation to next by genes |
| alleles | different forms of genes for the same trait, made of specific pieces of DNA and found in chromosome |
| genotype | genetic makeup of an organism |
| phenotype | physical characteristics of an organism |
| probability | the likelihood that an event will occur |
| homozygous | two of same alleles |
| heterozygous | two different alleles |
| independent assortment | genes can segregate independently during gamete formation |
| incomplete dominance | one allele is not completely dominant over other, blended mixture of trait |
| codominance | both alleles are dominant and show up in phenotype |
| multiple alleles | when genes have more than 2 alleles in a population, blood type |
| polygenic traits | traits that have several genes that interact, skin color |
| codominance in blood types | AB |
| i makes _____ | no proteins |
| genome | a complete set of genetic information |
| karyotype | picture of chromosomes arranged in homologous pairs, all homologs are the same size except sex chromosomes |
| sex chromosomes | male vs female (X and Y), two of 46 chromosomes, Y chromosome ONLY denotes maleness, X chromosome carries alleles |
| autosomes | all other chromosomes in an organism |
| pedigree | "genetic tree", allows tracking of disorders through generations, shows relationship between inherited traits within a family, based on observable traits, help understand probability of child with disorder |
| dominant traits | expressed in every generation |
| recessive traits | the expression may skip generations, carriers |
| colorblindness | color vision is determined by 3 genes on X chromosome, 1/10 males |
| reason why males are more prone to sex-linked genetic disorders | a defective version of any one of the alleles can lead to colorblindness |
| X-chromosme inactivation | females need to function off one X chromosome, so they randomly switch off one X chromosome (Barr Body), cat fur |
| nondisjunction | when meiosis doesn't work, leads to nondisjunction, homologous pairs fail to separate, abnormal #chromosomes in gametes, genetic disorders |
| chromosome | in nucleus, contains genes, passes genetic info. from one generation to the next |
| homologous chromosomes | chromosome pair, one from each parent, both code for same trait but have own alleles |
| diploid | a cell that contains both sets of homologous chromosomes (2N) |
| Haploid | a cell that contains one set of homologous chromosomes (n) |
| Meiosis | process of reduction division in which the number of chromosomes is cut in half and homologous chromosomes in a diploid cell are separated, only happens in gonads |
| Meiosis I | reduction, chromosome number needs to be cut in half, 2n --> n |
| prophase I | chromosomes shorten and thicken, chromosomes match up with homologous pairs (tetrad), crossing over begins, nuclear envelope disappears |
| Metaphase I | homologous chromosomes line up on equator of cell, independent assortment |
| Anaphase I | homologous chromosomes move ot poles of cell |
| Telophase I | set of doubled chromosomes goes to poles, nuclear membrane reappears, cytokinesis |
| Meiosis II | chromosomes split and become single-stranded, similar to mitosis |
| Prophase II | chromosomes re-condense, centrioles move to poles of cell |
| Metaphase II | chromosomes line up on equator of cell |
| Anaphase II | sister chromatids split apart at centromere |
| Telophase II | single-stranded chromosomes arrive at each pole and cytokinesis happens |
| Meisos vs. Mitosis | Mitosis produces 2 genetically identical diploid cells, Meiosis produces 4 genetically different haploid cells |
| Independent Assortment | each of the homologous chromosomes in a tetrad can go in a different direction, each set sorts itself out independent of the other sets, more chromosomes = more variation |
| crossing over | two homologous chromosomes exchange genetic material during prophase I, produces new combinations of alleles that will be present in gametes |
| genetic engineering | direct manipulation of an organism's genes, allows us to transfer DNA sequences (including entire genes) from one organism to another |
| Steven Howell | 1986, isolated gene from fireflies, inserted it into tobacco plants, expressed in tobacco plant |
| transgenic organisms | organisms that contain genes from another organism |
| uses of transgenic organisms | study genes, improve food supply |
| clone | a member of a population of genetically identical cells produced from a single cell, cows, pigs, sheep, mice |
| Ian Wilmut | scottish scientist that created Dolly in 1997 |
| how to clone | egg cell is extracted out of an egg, dono |
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