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DCBIO Genetics
Chapter 9 study guide
Question/Term | Answer/Definition/Example |
---|---|
What is Amniocentesis? | the sampling of amniotic fluid using a hollow needle inserted into the uterus, to screen for developmental abnormalities in a fetus. |
When is Amniocentesis done? | after 14 weeks |
Define allele | one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. |
True Breeding Dominant | AABB |
True Breeding Recessive | aabb |
Dominant | A |
Recessive | a |
Phenotypic ratio | 3:1 (dominant, recessive) |
Genotypic ratio | 1:2:1 (capital, capital, lowercase) |
Phenotype | trait expressed |
Genotype | alleles |
Mendel's Principle of Segregation and Law of Independent Assortment | Segregation = separation Independent = by themselves |
Incomplete Dominance | one allele does not completely dominate another allele, and therefore results in a new phenotype |
Co-Dominance | a condition in which the alleles of a gene pair in a heterozygote are fully expressed thereby resulting in offspring with a phenotype that is neither dominant nor recessive |
Polygenic | one of a group of nonallelic genes that together control a quantitative characteristic in an organism |
Monohybrid | Tt - one letter |
Dihybrid | TtDd - two letters |
Sex-Linked | X^a Y crossed with X^A X^a |
Gene Mapping | the process of determining where genes are located on individual chromosomes |
Linked Genes | genes that are found near each other on the same chromosome |
Blood Typing | the testing of a sample of blood to determine an individual's blood group |
Epistasis | occurs when two or more different gene loci contribute to the same phenotype, but not additively |
Epistatic | describes the relationship between the genes in epistasis |
Recombination | the rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms |
Pleiotropy | occurs when one gene influences two or more seemingly unrelated phenotypic traits |