Term
| Chromosome Theory of Inheritance |
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Definition
1902
- mendelian genes have specific loci on chromosomes, and it is the chromosomes that undergo segregation and independent assortment |
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Term
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Definition
early 1900s
- proved that genes are located on chromosomes through his work with fruit flies
- first indication of sex-linked genes because only males had white eyes |
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Term
| Why did Morgan use fruit flies? |
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Definition
• Easy to rear in lab
• Short generation time (approximately 10 days)
• Abundant offspring (100s per mating)
• Only 4 pairs of chromosomes
• Numerous mutation stocks now available |
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Term
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Definition
- the normal phenotype for a character (the phenotype most common in natural populations)
example: fruit flies with red eyes |
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Term
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Definition
- traits that are alternatives to the wild type
- assumed to have originated as mutations in the wild-type allele
example: fruit flies with white eyes |
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Term
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Definition
- linked genes are located on the same chromosome and tend to be inherited together in genetic crosses
- probability of gene linkage is related to the space between the genes on the chromosome
- goes against Mendel's law of independent assortment |
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Term
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Definition
- the production of offspring with combinations of traits differing from those found in either parent
- identified by Morgan
mechanism: crossing over |
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Term
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Definition
| - offspring that inherit a phenotype identical to one of the parental phenotypes |
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Term
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Definition
| - offspring whose phenotypes are nonparental (do not match the phenotypes of either parent) |
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Term
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Definition
- the process that breaks the physical connection between genes on the same chromosome (one maternal and one paternal chromatid break at corresponding points and then are rejoined to each other?)
- allows for recombinant types
- the mechanism that Morgan purposed to support the idea of genetic recombination |
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Term
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Definition
| - an ordered list of the genetic loci along a particular chromosome |
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Term
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Definition
- the frequency with which crossing over will occur depends upon the distance between the genes on a chromosome
- the farther apart two genes are, the higher the probability that a crossover will occur between them and therefore they will have a higher recombination frequency |
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Term
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Definition
- genes located on either sex chromosome
- historically related to genes inherited on the X-chromosome in humans |
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Term
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Definition
- general term for the chromosomal alteration that causes an organism to inherit more than two chromosome sets
- common in the plant kingdom |
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