Linkage of chromosome mapping in eukaryotes

what are 2 mechanisms that generate diversity during sexual reproduction in eukaryotes

-independent assortment

-homologous recombination

what is independent assortment and how does in generate genetic diversity

-independent assortment of chromosomes during meiosis

-humans have 23 pairs, one of each pair randomly turns into gamete

-gives 2²³ = over 8 million gamete options per individual

when does homologous recombination happen

-during prophase I of meiosis

what is homologous recombination

-during prophase I of meiosis

-homologous chromosomes pair up and non sister chromatids cross over

-exchange equal segments of DNA based on sequence similarity

-no genes or nucleotides are gained or lost

-physical crosses are chiasmata

how many chiasmata typically form per chromosome pair per meiosis

-1 to 3

what is genetic linkage

-when genes are inherited together they are linked

link between cross over and distance between genes

-the closer together the 2 genes are the less chance there will be cross over between them and more likely 2 alleles will be inherited together

how can you estimate the physical distance between 2 linked genes

-number of recombination events

what are parental types

-chromosomes that look exactly like original parents

-no recombination between genes you’re tracking

what are recombinants

-chromosomes where crossover has shuffled the alleles into new combinations that didnt exist in parents

what is the recombination frequency (RF)

-total number of recombinants divided by total progeny

-expressed as a percentage

-in map units

how to calc RF

what is a map unit

-often called centimorgans

-length of DNA where recombination occurs in every hundred attempts