Variation chromosome structure & number 3 Flashcards
Genetic variation
Genetic differences among members of the same species
How are chromosomes classified?
- Location of centromere
- Size
- Banding pattern
What are the classification of centromeres?
- Metacentric
- Submetacentric
- Acrocentric
- Telocentric
Metacentric
The centromere is near the middle
Submetacentric
The centromere is slightly off the center
Acrocentric
The centromere is significantly off the center but not at the end
Telocentric
The centromere is at one end
Since chromsomes aren’t directly connected in the middle they have a ________ & _________
Long arm & Short arm
In a _________ chromsomes are numbered based on size where larger chromosomes have lower number such as (1,2,3) & smaller chromsomes have higher number like (21, 23)
Karyotype
What are the different type of chromsome mutations?
- Deletions
- Duplication
- Inversions
- Translocation
Deletion
A segment of genetic material is missing (Deficiency- describes the region missing in a chromsome)
Duplication
A section of a chromsome is repeated more than once
Inversion
Involves a change in the direction of the genetic material along a chromosome
Translocation
Occurs when one segment of a chromosome become attatched to a different chromosome or to different part of the same chromosome
Simple translocation
Occur when a single piece of chromsome is attatched to another chromsome
Reciporcal translocation
Two different chromsome exchange peices
___________ & ____________ changes the total amount of genetic material in a chromsome
Deletion & Duplication
__________ & ____________ are chromsomes rearrangments
Inversion & Translocation
A chromosome _______ occurs when a chromosome break in one or more places & a fragment of the chromosome is lost
Deletion
_____________ usually have a negative effect on a phenotype speically when there is a large amount
Deletion
____________ can occur because of crossing over
Duplication
Repetitive sequence
Sequence on a chromosome that occur multiple times
Nonallelic homologous recombination
Crossing over between repetitive sequences from two different genes which results in one chromosome being duplicated & the other has deletion
____________ results in extra genetic material
Gene duplication
Duplication only affect the phenotype if a ________ amount is duplicated
Large
Copy number variation (CNV)
Structural variation in which a segment of DNA has a copy number different among members of the same species (May b caused by duplication)
Segmental Duplication
Results in a homlog with two copies of a the same gene
A chromosome with an _________ contains a segment that has been flipped so that it runs in the opposite direction
Inversion
What are the different classification of inversion base on the centromere?
- Pecentric Inversion
- Paracentric Inversion
___________ dont have an negative effect on the phenotype because when a chromosome contains an the total amount of genetic material remains the same
Inversion
__________________ may produce abnormal chromosome due to crossing over
Inversion Heterozygote
Inversion Heterozygote
An individual carrying one normal copy of a chromosome & one copy with an inversion
An individual carrying __________ amounts of inversion is more likely to produce abnormal gametes
Large
____________ involves the change between different chromosome
Translocation
In _______________ a piece from one chromosome is attatched to anohter chromosome
Translocation
Balanced Translocation
Translocation that doesn’t change the amount of genetic material (Doesn’t have a negative effect on the phenotype)
Individuals with _______________ may produce abnormal gametes due to the pairing & segregation of chromosome
Reciprocal Translocation
Individuals who carry _______________ have a greater risk of producing gametes with unbalanced combination of chromosomes
Balanced Translocation
Euploid
Have a chromosome number that is an exact multiple of a chromsome set (Ex. 8 chromosome with 2 sets of 4, 8/4 =2 )
Aneuploid
Alteration in the number of chromosomes so the total number is not an exact multiple of a set (Ex A fly having 9 chromsomes instead of 8 )
____________ causes an imbalance in gene expression that causes it to have a negative effect on the phenotype
Aneuploidy
Changes in the number of sets of chromsomes is referred to as _______________
Varaition in Euploidy
Nondisjunction
Chromosomes dont segregate properly
Meiotic nondisjunction
Can produce cells that have too many or too few chromosome
Meiotic nodisjucntion can produce ______________ or _____________
Aneiploidy or Polyploidy
Changes in euploidy occur by what?
Auropolploidy, Alloploidy, & Allopolploidy
Autopoluploid
Has one or more extra set of chromosomes
Alloploidy
Results of interspecies crosses
A deletion that occurs in the middle of a chromosome is called __________
Interstitial
The globin gene family includes genes for the proteins _________ and _________
Hemoglobin Myoglobin
What chromosome mutation is the cause of Angelman syndrome and Prader-Willi syndrome ?
Deletion
__________ may arise from nonallelic homologous recombination
Deletion & Duplication
In a ___________ inversion, the centromere lies outside the inverted region of a chromosome
Paracentric
Paracentric Inversion
Inversion that includes the centromere
Paracentric inversion
Inversion that doesn’t include the centromere
_____________ are usually the result of the loss (deletion) of serval genes
Syndromes (Ex. Cri-du-chat syndrome)
__________ & ____________ results in chromosomes forming a cross pattern during meiotic pairing
Inversion & translocation
____________ can result in the formation of a chromosome with a dicentric bridge
Inversion
___________ usually caused by modifications to the telomere of the chromosome
Translocation
__________ causes homologous chromosomes to form a loop during meiotic pairing
Inversion
