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| 6491906450 | Alleles | The different forms of a gene. Y and y are different alleles of the gene that determines seed color. Alleles occupy the same locus, or position, on chromosomes. | 0 | |
| 6491906451 | Autosomal | A locus on any chromosome but a sex chromosome. Not sex-linked. | 1 | |
| 6491906452 | co-dominant alleles | Two different alleles at a locus are responsible for different phenotypes, and both alleles affect the phenotype of the heterozygote. For example, consider blood type in which an individual who inherits both A and B alleles will express both proteins on the blood cell's surface. | 2 | |
| 6491906453 | complete linkage | Complete linkage describes the inheritance patterns for 2 genes on the same chromosome when the observed frequency for crossover between the loci is zero. | 3 | |
| 6491906454 | dominant trait | A trait expressed over another trait. | 4 | |
| 6491906455 | Drosophila melanogaster | The fruit fly, a favorite organism for genetic analysis. | 5 | |
| 6491906456 | Epistasis | One gene masks the expression of a different gene for a given trait. Ex: fur color in labrador retreivers | 6 | |
| 6491906457 | F1 generation | First filial; Offspring of a cross between two parents for a trait of interest | 7 | |
| 6491906458 | F2 generation | Second filial;Offspring of a cross involving the F1 generation. | 8 | |
| 6491906459 | Genotype | The genes inherited for a given trait. For a single trait on an autosome, an individual can be homozygous for the dominant trait, heterozygous, or homozygous for the recessive trait. | 9 | |
| 6491906460 | Heterozygous | Differing alleles for a trait in an individual, such as Yy. | 10 | |
| 6491906461 | homologous chromosomes | The pair of chromosomes in a diploid individual that have the same overall genetic content. | 11 | |
| 6491906462 | Homozygous | Both alleles for a trait are the same in an individual. They can be homozygous dominant (YY), or homozygous recessive (yy). | 12 | |
| 6491906463 | Hybrid | heterozygous; usually referring to the offspring of two true-breeding (homozygous) individuals differing in the traits of interest. | 13 | |
| 6491906464 | incomplete dominance | Intermediate phenotype in F1, parental phenotypes reappear in F2. The flowers of the snapdragon plant can be red, pink, or white. Color is determined at a single locus. The genotype RR results in red flowers and rr results in white flowers. The heterozygote genotype of Rr results in pink flowers. When the heterozygote has a different, intermediate phenotype compared to the homozygous dominant or homozygous recessive individuals. | 14 | |
| 6491906465 | lethal alleles | Mutated genes that are capable of causing death. | 15 | |
| 6491906466 | Linkage | genes that are inherited together on the same chromosome. Three inheritance patterns are possible: non-linkage (independent assortment), Partial linkage, and complete linkage. | 16 | |
| 6491906467 | mendel's law of independent assortment of alleles | Alleles of different genes are assorted independently of one another during the formation of gametes. | 17 | |
| 6491906468 | mendel's law of segregation | Alleles segregate from one another during the formation of gametes. | 18 | |
| 6491906469 | monohybrid cross | Cross involving parents differing in only one trait. | 19 | |
| 6491906470 | Mutation | Change in the DNA sequence of a gene to some new, heritable form. Generally, but now always a recessive allele. | 20 | |
| 6491906472 | partial linkage | Partial linkage describes one of the inheritance patterns for 2 genes on the same chromosome, when the expected frequency for crossover between the loci is greater than zero but less than one. From partial linkage analysis we can learn about the order and spacing of genes on the same chromosome. | 21 | |
| 6491906473 | Phenotype | The physical appearance of an organism with respect to a trait, i.e. yellow (Y) or green (y) seeds in garden peas. The dominant trait is normally represented with a capital letter, and the recessive trait with the same lower case letter. | 22 | |
| 6491906474 | Pleiotropic | A single gene determines more than one phenotype for an organism. ex: coloration of siamese cat and cross eyes | 23 | |
| 6491906475 | recessive trait | The opposite of dominant. A trait that is masked when the dominant allele is present. | 24 | |
| 6491906476 | sex chromosomes | Sex determination is based on sex chromosomes; X chromosome does contain additional genes | 25 | |
| 6491906477 | sex-linked | A gene coded on a sex chromosome, such as the X-chromosome linked genes of flies and man. | 26 | |
| 6491906479 | true-breeding | Homozygous for the true-breeding trait. | 27 | |
| 6491906480 | wild-type allele | The non-mutant form of a gene, encoding the normal genetic function. Generally, but not always a dominant allele. | 28 | |
| 6491906481 | Principles of Dominance | In the heterozygous individual the dominant trait will be expressed | 29 | |
| 6491906482 | incomplete dominance | a condition in which a trait in an individual is intermediate between the phenotype of the individual's two parents because the dominant allele is unable to express itself fully | 30 | |
| 6491906483 | hybrid | offspring of crosses between parents with different traits | 31 | |
| 6491906484 | homozygous | having identical alleles at corresponding chromosomal loci | 32 | |
| 6491906485 | heterozygous | having dissimilar alleles at corresponding chromosomal loci | 33 | |
| 6491906486 | Punnett square | a chart that shows all the possible combinations of alleles that can result from a genetic cross | 34 | |
| 6491906487 | test cross | the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype | 35 | |
| 6491906488 | dihybrid cross | A cross between two individuals, concentrating on two definable traits | 36 | |
| 6491906489 | pedigree | a diagram that shows the occurrence of a genetic trait in several generations of a family | 37 | |
| 6491906490 | mutations | Random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity | 38 | |
| 6491906491 | multiple alleles | three or more forms of a gene that code for a single trait; ex: ABO blood group | 39 | |
| 6491906492 | codominance | inheritance pattern in which a heterozygote expresses the distinct traits of both alleles | 40 | |
| 6491906493 | penetrance | The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype. | 41 | |
| 6491906494 | expressivity | the degree to which a genotype is expressed in an individual | 42 | |
| 6491906495 | genetic linkage | tendency for alleles of genes on the same chromosome to be inherited together | 43 | |
| 6491906496 | recombination frequency | percentage of recombinants, meaning percentage of of offspring that had traits from crossover. recombination frequencies are lower when alleles are closer together. | 44 | |
| 6491906497 | map units | A measurement of the distance between genes; one map unit is equivalent to a 1 percent recombination frequency. | 45 | |
| 6491906498 | sex-linked inheritance | An inheritance pattern whereby genes carried on the sex chromosomes (the X and the Y) are more likely to be expressed in males because they only have one X chromosome. | 46 | |
| 6491906500 | SRY gene | a gene, located on the Y chromosome, that functions as a master switch, committing the sex of a developing embryo to "male." | 47 | |
| 6491906502 | carrier | individual who has one copy of the allele for a recessive disorder and does not exhibit symptoms | 48 | |
| 6492054646 | Karyotype | Representation of the number and visual appearance of the chromosomes in the cell nuclei of an organism or species; will show chromosomal disorders such as Down syndrome | 49 | |
| 6492192566 | Polygenic traits | Physical traits that are the result of multiple genes being expressed; ex: skin color, hair color | 50 | |
| 6492213756 | Gregor Mendel | The father of genetics; studied pea plants and established the particle theory of inheritance as well as law of segregation and independent assortment | 51 | |
| 6492228616 | Thomas Hunt Morgan | Studied fruit flies and determined that genes can be linked on the same chromosome | 52 | |
| 6492246875 | Environmental influence | Environmental conditions can influence phenotype; temperature, light and pH can help determine appearance | 53 | |
| 6492272371 | mutation | a change in DNA | 54 | |
| 6492275331 | Chromosome mutation | A mutation in which a portion of chromosome is lost or added; ex: translocation | 55 | |
| 6492284068 | Gene mutation | A mutation in which a given gene is changed; ex: substitution, insertion or deletion of nucleotide | 56 | |
| 6492311734 | Chi square | a statistical method assessing the goodness of fit between observed values and those expected theoretically; used in genetics to compare offspring data to those projected by Punnett squares | 57 |
