Transitional B cells bound for a follicular fate undergo positive and negative selection in the spleen.

TLS Online TPP Program

#Id: 9208

#Section 3: Genetics, Cellular and Molecular Biology

CAUSES OF GENETIC DRIFT

Genetic drift in a small population over multiple generations can significantly affect the composition of a population’s gene pool. 

TLS Online TPP Program

#Id: 9209

#Section 3: Genetics, Cellular and Molecular Biology

Founder effect

A few individuals form a population start a new population with a different allele frequency than the original population.

Sampling error can arise is through the founder effect, which results from the establishment of a population by a small number of individuals.

TLS Online TPP Program

#Id: 9210

#Section 3: Genetics, Cellular and Molecular Biology

Genetic bottleneck

Genetic drift arises is through a genetic bottleneck, which develops when a population undergoes a drastic reduction in size

TLS Online TPP Program

#Id: 9211

#Section 3: Genetics, Cellular and Molecular Biology

THE MAGNITUDE OF GENETIC DRIFT

n  = population size

pq=allelic frequency

sp2=variance in allelic frequency among the populations

TLS Online TPP Program

#Id: 9212

#Section 3: Genetics, Cellular and Molecular Biology

Loss of their original diversity per generation

=1/2n

Gain of their original diversity per generation

=1/2n 

Gain or Loss of their original diversity per generation

=1/4n

TLS Online TPP Program

#Id: 9213

#Section 3: Genetics, Cellular and Molecular Biology

Probability of being heterozygote in given population

H = 1 - 1/2N