What may prevent linked genes from being inherited together
If they’re separated by chiasmata
Key Terms
What may prevent linked genes from being inherited together
If they’re separated by chiasmata
W/ crossing over in autosomal linkage
Genotypic and phenotypic ratios are variable
Parental types > cross-over type
Proportion depends on how often cross overs ocurred be...
Recombinant offspring
Offspring w/ a diff combination of alleles to either parent
Closer genes are located on a chromosome …
Less likely to be separated during crossing over –> fewer recombinant offspring
Recombination frequency
Measure of amont of crossing over occured in meoisis - indicating level of linkage
Also used to map genes loci ; 1% = distance of 1 map unit ...
Calculating recombinant frequency
No of recombinant offspring/ total no. of offspring
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
What may prevent linked genes from being inherited together | If they’re separated by chiasmata |
W/ crossing over in autosomal linkage | Genotypic and phenotypic ratios are variable Parental types > cross-over type Proportion depends on how often cross overs ocurred between two loci |
Recombinant offspring | Offspring w/ a diff combination of alleles to either parent |
Closer genes are located on a chromosome … | Less likely to be separated during crossing over –> fewer recombinant offspring |
Recombination frequency | Measure of amont of crossing over occured in meoisis - indicating level of linkage Also used to map genes loci ; 1% = distance of 1 map unit on chromosome |
Calculating recombinant frequency | No of recombinant offspring/ total no. of offspring |
50% recombination frequency | No linkage, separate chromosomes |
<50% recombination frequency | Gene linkage and IA has been hindered Signifies autosomal linkage Linked genes are inherited together Crossing over produces few recombinant offspring |
Homozygous | Has identical alleles on both chromosome |
H0 in chi squared | There is no sig. difference between expected and observed values |
Degrees of freedom in chi squared | No. of categories - 1 |
Epistasis | Interaction of genes at diff loci Genes masking the expression of other genes (not alleles) Gene regulaion is a example w. reg . genes controlling structural genes |
When can epistasis be seen | Multistep reactions |
Hypostatic | Gene affected by another gene | Cause the phenotype |
Epistatic gene | Gene that affects the expression of another gene; can happen as a result of dominant or recessive alleles |
Epistatic alleles | Another pair of alleles found at diff loci |
Antagonistic epistasis | Dominant and recessive epistasis |
Dominant epistasis | If there are ANY dominant alleles present in the epistatic alleles, masks expression of hypostatic alleles |
Phenotypic ratio in a heterozygous dihybid cross w/ dominant epistasis | 12:3:1 |
Recessive epistasis | Occurs when a pair of homozygous recessive alleles at one gene locus masks the expression of the hypostatic allele at a 2nd locus |