chapter 10.5 Flashcards
Genes on the same chromosome maybe
alleles of a gene are from homologous pairs so are packaged in
How do a few chromosome control so many genes
Each chromosome carries many genes
Are carried on the same chromosome, they are inherited together .
They do not assort independently during meiosis
comparisons between genes and chromosomes
- they both come in pairs
2.alles of a gene are packaged into separate gametes
. so are members of homlogous pairs
- Both are inherited in random combinations
The affect of gene linkage on dihybrid cross versus no gene linkage
When Genes are not lined on the same chromosome they assort independently
The gametes then represent all possible allele combinations, and the cross yields the expected phenotypic ratio.
When genes are linked on the same chromosome, only two allele combinations are expected in the gametes, and the number of phono types are reduced
collection of genes that tend to be inherited together
Why do offsprings sometimes have trait combinations not seen in either parent
CROSSING OVER : an exchange of genetic material between homologous chromosomes during prophase I
. After crossing over no two chromatids in a homologous pair of chromosome are identical
What is the purpose and end result of CROSSING OVER
no 2 chromatids in a homologous pair of chromosomes are identical
2 options of chromatids of that a gamete could inherit after crossing over
- Parent chromatid
2. Recombinant chromatid
retains the allele combination from each parent.
the result of two genes crossing over; has a mixture of maternal and paternal genes
diagrams of gene order and spacing on chromosomes ( vertically).
It shows the likelihood of a gene allele being seperated from another based on theirs pacing
What concept are linkage maps based on
the farther apart 2 alleles are on the same chromosome, the more likely crossing over is to separate them- simply because more separates the genes
How are linkage maps used
By determining the the percentage of recombinant offsprings, one can infer how far apart the genes are on the chromosome