Term
| Chromosome Theory of Inheritance |
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Definition
– Mendelian genes have specific loci (positions) on
chromosomes
– Chromosomes undergo segregation and independent
assortment |
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| Experimented with fruit flies provided evidencet that chromosomes are the location of Mendel's heritable factors |
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| Characteristics that make Fruit Flies a convenient organism for genetic studies: |
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Definition
– They breed at a high rate
– A generation can be bred every two weeks
– They have only four pairs of chromosomes |
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| Traits alternative to the wild type |
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Definition
| It is on the Y chromosome and it codes for the development of testes |
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Definition
Diploid=Female
Haploid=Male |
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Term
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Definition
- A gene located on either sex chromosome.
- In humans, sex-linked usually refers to a gene on the larger X chromosome. |
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Term
| For a recessive sex-linked trait to be expressed... |
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Definition
– A female needs two copies of the allele
– A male needs only one copy of the allele
(more common in males than in females) |
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Term
| Some disorders caused by recessive alleles on the X chromosome: |
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Definition
- Color blindness
- Duchenne muscular dystrophy
- hemophilia |
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Term
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Definition
| the inactive X condenses. If the female is heterozygous for a particular gene located on the X chromosome, she will be a mosaic for that character. |
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Definition
| Genes located on the same chromsome tending to be inherited together. |
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Definition
| The production of offspring with combinations of traits differing from either parent |
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Definition
| Offspring with a phenotype matching one of the parental phenotypes |
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Definition
- Offspring with nonparental phenotypes (new combination of traits)
- A 50% frequency of recombination is observed for any two genes on different chromsomes |
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Definition
| An ordered list of the genetic Loci along a particular chromsome |
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Definition
- Constructed a genetic Map
- Sturtevant predicted that the farther apart two
genes are, the higher the probability that a
crossover will occur between them and
therefore the higher the recombination
frequency |
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Term
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Definition
| a genetic map of chromosome based on recombination frequences |
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Term
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Definition
- Distances between genes.
- Expressed as one map unit, or centimorgan, represents a 1% recombination frequency
- Map units indicate relative distance and order, not precise locations of genes |
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Term
| Far apart genes on the same chromosome... |
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Definition
| can have recombination frequency near 50% |
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Term
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Definition
| indicate teh positions of genes with respect to chromosomal features |
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Term
| Large-scale chromosomal alterations often lead to... |
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Definition
spontaneous abortions (miscarriages)
or cause a variety of developmental disorders |
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Term
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Definition
- pairs of homologous chromosomes do not separate normally during meiosis
- As a result, one gamete receives two of the same type of chromosome, and another gamete receives no copy. |
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Term
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Definition
| results from the fertilization of gametes in which nondisjunction occured (they have an abnormal number of a particular chromosome.) |
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Definition
| Has only one copy of a particular chromosome |
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Definition
| has three copies of a particular chromosome |
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Definition
Condition in which an organism has more than two complete sets of chromosomes
(more common in plants, but not animals) |
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Definition
| (3n) three sets of chromosomes |
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Definition
| (4n) four sets of chromosomes |
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Term
| Breakage of a chromosome can lead to four types of changes in chromosome structure: |
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Definition
Deletion
Duplication
Inversion
Translocation |
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Term
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Definition
| removes a chromosomal segment |
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Term
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Definition
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Definition
| reverses a segment within a chromosome |
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Definition
| moves a segment from one chromosome to another |
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Definition
| an enuploid condition that results from three copies of chromosome 21 |
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Term
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Definition
| The result of an extra chromosome in a male, producing XXY individuals |
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Term
| Monosomy X or Turner Syndrome |
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Definition
| Produces X0 females, who are sterile; it is teh only know viable monosomy in humans |
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Term
| Cri Du Chat ("cry of the cat") |
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Definition
- Results from a sepcific deletion in chromosome 5.
- Mentally retarded and has a catlike cry; individuals usually die in infancy or early childhood |
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Term
| Chronic Myelogenous Leukemia (CML) |
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Definition
| Caused by translocations of chromosomes |
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Definition
| The phenotype depends on which parents passed along the alleles for those traits. |
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Definition
- Genes found in organelles in teh cytoplasm.
- Mitochondria, chloroplasts, and other plant plastids carry small circular DNA molecules |
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Term
| Mitochondrial Myopathy and Leber's heridtary optic neuropathy |
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Definition
| Defect in mitochondrial genes preventing cells from making enough ATP and result in diseases that affect the muscular and nervous systems. |
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