Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes

Klug - Essentials of Genetics 10th Edition

Klug10th EditionEssentials of GeneticsISBN: 9780135588789Non è quello che usi tu?Cambia libro di testo

Klug 10th Edition

Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes

Problema 6

Capitolo 7, Problema 6

Why are double-crossover events expected less frequently than single-crossover events?

Guida verificata passo dopo passo

Understand that a crossover event during meiosis involves the exchange of genetic material between homologous chromosomes, which can occur at various points along the chromosome.

Recognize that a single-crossover event involves one exchange between chromatids, while a double-crossover event involves two separate exchanges occurring at different locations on the same chromosome.

Recall that the probability of crossover events depends on the physical distance between genes: the farther apart two loci are, the higher the chance of crossover between them.

Since double-crossover events require two independent crossover events to happen on the same chromosome, their probability is the product of the probabilities of each single crossover, making it inherently lower than a single crossover event.

Therefore, double-crossover events are less frequent because they depend on two separate crossover occurrences happening simultaneously, which is statistically less likely than just one crossover event.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Durata del video:

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Crossing Over

Crossing over is the process during meiosis where homologous chromosomes exchange genetic material. This recombination increases genetic diversity by producing new allele combinations. It typically occurs at specific points called chiasmata along the chromosome.

Video consigliato:

Percorso guidato

05:19

Discovery of Crossing Over

Single vs. Double Crossover Events

A single crossover involves one exchange between homologous chromosomes, while a double crossover involves two separate exchanges. Double crossovers are less frequent because they require two independent recombination events occurring close together on the same chromosome.

Video consigliato:

Percorso guidato

06:14

Multiple Cross Overs and Interference

Probability of Recombination Events

The likelihood of crossover events depends on the physical distance between genes; single crossovers are more common because they need only one event. Double crossovers require two events, making their probability the product of two independent crossover probabilities, thus less frequent overall.

Video consigliato:

Percorso guidato

07:41

Probability

Pratica correlata

Domanda del libro di testo

What two essential criteria must be met in order to execute a successful mapping cross?

681

views

Domanda del libro di testo

The genes dumpy (dp), clot (cl), and apterous (ap) are linked on chromosome II of Drosophila. In a series of two-point mapping crosses, the following genetic distances were determined. What is the sequence of the three genes?

dp–ap: 42

dp–cl: 3

ap–cl: 39

948

views

Domanda del libro di testo

Explain why a 50 percent recovery of single-crossover products is the upper limit, even when crossing over always occurs between two linked genes?

1034

views

Domanda del libro di testo

Describe the cytological observation that suggests that crossing over occurs during the first meiotic prophase.

828