BIO220 READING SUMMARIES
Study Notes – Required Readings
Reading 1: Genetic Rescue (Examples of Mexican Wolves, Florida Panthers)
• Population with low fitness, showing extinction risk = genetic rescue is advocated, where
unrelated individuals from a different location/isolated population added
• In small population, inbreeding depression is seen, which is a negative affect on fitness due to
increased homozygosity and exposure of detrimental alleles from inbreeding
• How to avoid this: reduce mean kinship between parents, attempt to maximize the effective
population size
• Genetic load – decreased fitness due to poor genetic standing, where mutation in populations
become fixed and in high frequency
• Guidelines for genetic rescue:
◦ Should be greater benefits of translocation of individuals than costs (new diseases, etc)
◦ There should be evidence of low fitness/high inbreeding in endangered population so that
an introduction would be likely to increase fitness and reduce inbreeding
◦ A closely related donor population needs to be available so outbreeding depression is low
(low fitness from breeding crosses) ---> same species from a similar habitat
◦ Experimental data should be gathered to show success in simulations
◦ Protocol should be put in place to reduce negative non-genetic effects like only introducing
females to avoid male aggression
◦ Thoroughly monitor further generations, mating, reproduction so you can better manage the
population and its genetics – tracking maternity/paternity
◦ Potential for management continuation – flexibility in cases where results are not as
expected such as if one individual introduction was less successful, be able to have another
to introduce. If ancestry from donor population is more than wanted or expected, further
introductions should not occur.
◦ Avoid swamping of local genetic variation by introducing too much new ancestry cause this
could be maladaptive to the locality of the endangered population, avoid complete genetic
replacement of the population
◦ Avoid low effective in subsequent generations of the population by introducing migrants,
and ensuring they all have equal contribution rather than one being in high proportion of the
gene pool
• Genetic rescue may result in only short lived fitness increase, and inbreeding depression may
again be increased. Extinction is only temporarily avoided, giving time to fix environmental or
other factors that cause endangerment
• To increase genetic health, effective population sizes need to be increased
• Genetic recovery to increase genetic variation in neutral genes may also improve rescue efforts
, Mexican Wolf Genetic Rescue:
• Two lineages that were isolated crossed while in captivity to increase heterozygosity, fitness,
and reduce inbreeding. Cross-lineages released in wild had more pups than high inbreeding
groups, and a lower inbreeding coefficient through subsequent generations.
• Captive populations suffered from high genetic load – seen in smaller body size
• Negative effects of management: level of ancestry is seen higher from one of the lineages
Study Notes – Required Readings
Reading 1: Genetic Rescue (Examples of Mexican Wolves, Florida Panthers)
• Population with low fitness, showing extinction risk = genetic rescue is advocated, where
unrelated individuals from a different location/isolated population added
• In small population, inbreeding depression is seen, which is a negative affect on fitness due to
increased homozygosity and exposure of detrimental alleles from inbreeding
• How to avoid this: reduce mean kinship between parents, attempt to maximize the effective
population size
• Genetic load – decreased fitness due to poor genetic standing, where mutation in populations
become fixed and in high frequency
• Guidelines for genetic rescue:
◦ Should be greater benefits of translocation of individuals than costs (new diseases, etc)
◦ There should be evidence of low fitness/high inbreeding in endangered population so that
an introduction would be likely to increase fitness and reduce inbreeding
◦ A closely related donor population needs to be available so outbreeding depression is low
(low fitness from breeding crosses) ---> same species from a similar habitat
◦ Experimental data should be gathered to show success in simulations
◦ Protocol should be put in place to reduce negative non-genetic effects like only introducing
females to avoid male aggression
◦ Thoroughly monitor further generations, mating, reproduction so you can better manage the
population and its genetics – tracking maternity/paternity
◦ Potential for management continuation – flexibility in cases where results are not as
expected such as if one individual introduction was less successful, be able to have another
to introduce. If ancestry from donor population is more than wanted or expected, further
introductions should not occur.
◦ Avoid swamping of local genetic variation by introducing too much new ancestry cause this
could be maladaptive to the locality of the endangered population, avoid complete genetic
replacement of the population
◦ Avoid low effective in subsequent generations of the population by introducing migrants,
and ensuring they all have equal contribution rather than one being in high proportion of the
gene pool
• Genetic rescue may result in only short lived fitness increase, and inbreeding depression may
again be increased. Extinction is only temporarily avoided, giving time to fix environmental or
other factors that cause endangerment
• To increase genetic health, effective population sizes need to be increased
• Genetic recovery to increase genetic variation in neutral genes may also improve rescue efforts
, Mexican Wolf Genetic Rescue:
• Two lineages that were isolated crossed while in captivity to increase heterozygosity, fitness,
and reduce inbreeding. Cross-lineages released in wild had more pups than high inbreeding
groups, and a lower inbreeding coefficient through subsequent generations.
• Captive populations suffered from high genetic load – seen in smaller body size
• Negative effects of management: level of ancestry is seen higher from one of the lineages
