BIOLOGY CHAPTER 15
Terms
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- Chromosomal theory of inheritance
- mendelain genes have specific loci on chromosomes and it is chromosomes that undergo segregation and independent assortment
- wild type
- the most common phenotype for a character the phenotype most common in a natural population
- mutant phenotype
- traits that are alternative to the wild type
- sex linked genes
- genes located on the sex chromosomes
- linked genes
- genes located on the same chromosome which tend to be inherited together in genetc crosses because the chromosome is passed along as a unit
- genetic recombination
- offspring with new combinations of traits inherited by two parents q
- recombinants
- when offspring have different combinations of phenotypes than their parents
- linkage map
- a genetc map based on the combination frequencies
- cytological map
- maps that locate genes with a respect to chromosomal features
- Duchenne muscular dystrophy
- affects one in 3500 males in us rarely live past 20's progressice weekening of the muscles and loss of coordination
- hemophilia
- a sex linked reccesive trait of a certain protein required for blood clotting
- barr body
- the inactive x in each cell of a female condenses into a compact ovject called the bb which is in the nucleur envelope
- Nondissjunction
- a misshap
- poly ploidy
- when someone has more than a full set of chromosomes
- Duplication
- when a fragment joins to a homologous chromosome
- inversion
- when it reattaches to a chromosome
- aneuploidy
- if either of the abarrent gamets units with a normal one at fertilization the offspring all have an abnormal chromosome number
- trisomic
- if the chromosome is present in triplicate in triplicate in the fertilized egg (2nt chromosomes)
- monosomic
- if a chromosome is missing (2n-1 chromosome0 then the aneuploid cell is monosomic
- deletion
- occurs when a cromosome fragemnt lacking a centromere is lost during cell division
- Translocation
- a 4th possive result of of chromosomal breakage is for the fragment to join a non homologous chromosome
- down syndrome
- aneuploidy condition affecting appearence in 700 kids in the us extra chromosome 21
- fragile x syndrom
- 1/2500 females retardation part of x chromosome hangs on by a thread