Chapter 4: Molecular Genetics and Development

FIGURE 4. 1. Genes, termite workers, and queens FIGURE 4.1. Genes, termite workers, and queens. (A) Queen Cryptotermes secundus (bottom left) with male (top right) and workers. (B) Butting among workers in colonies with queen and without queens. (C) and (D) Butting before and after treatment of the queen with Neofem2 small interfering RNA (siRNA) and control siRNA. (Photo credit: Korb, J., et al (2009). Science, 324, 758–758)

FIGURE 4. 1a. Genes, termite workers, and queens FIGURE 4.1a. Genes, termite workers, and queens. (A) Queen Cryptotermes secundus (bottom left) with male (top right) and workers. (B) Butting among workers in colonies with queen and without queens. (C) and (D) Butting before and after treatment of the queen with Neofem2 small interfering RNA (siRNA) and control siRNA. (Photo credit: Korb, J., et al (2009). Science, 324, 758–758)

FIGURE 4. 1b. Genes, termite workers, and queens FIGURE 4.1b. Genes, termite workers, and queens. (A) Queen Cryptotermes secundus (bottom left) with male (top right) and workers. (B) Butting among workers in colonies with queen and without queens. (C) and (D) Butting before and after treatment of the queen with Neofem2 small interfering RNA (siRNA) and control siRNA. (Photo credit: Korb, J., et al (2009). Science, 324, 758–758)

FIGURE 4. 1c. Genes, termite workers, and queens FIGURE 4.1c. Genes, termite workers, and queens. (A) Queen Cryptotermes secundus (bottom left) with male (top right) and workers. (B) Butting among workers in colonies with queen and without queens. (C) and (D) Butting before and after treatment of the queen with Neofem2 small interfering RNA (siRNA) and control siRNA. (Photo credit: Korb, J., et al (2009). Science, 324, 758–758)

FIGURE 4. 1d. Genes, termite workers, and queens FIGURE 4.1d. Genes, termite workers, and queens. (A) Queen Cryptotermes secundus (bottom left) with male (top right) and workers. (B) Butting among workers in colonies with queen and without queens. (C) and (D) Butting before and after treatment of the queen with Neofem2 small interfering RNA (siRNA) and control siRNA. (Photo credit: Korb, J., et al (2009). Science, 324, 758–758)

FIGURE 4. 2a. Satellite and independent ruff males FIGURE 4.2a. Satellite and independent ruff males. Some of the differences in the mating behavior of (A) satellite males and (B) independent males are controlled by a single gene with two alleles labeled S and s. (Photo credits: BS Thurner Hof).

FIGURE 4. 2b. Satellite and independent ruff males FIGURE 4.2b. Satellite and independent ruff males. Some of the differences in the mating behavior of (A) satellite males and (B) independent males are controlled by a single gene with two alleles labeled S and s. (Photo credits: BS Thurner Hof).

FIGURE 4. 3. Quantitative Trait Loci Mapping FIGURE 4.3. Quantitative Trait Loci Mapping. Quantitative Trait Loci (QTL) mapping allows researchers to find the general region of the genome in which quantitative trait loci reside by using marker loci that are easily assayed, but unrelated to the trait in question, in order to identify the approximate locations of the unknown alleles that do affect the trait of interest. (From Bergstrom and Dugatkin, 2012)

FIGURE 4. 3. Quantitative Trait Loci Mapping FIGURE 4.3. Quantitative Trait Loci Mapping. Quantitative Trait Loci (QTL) mapping allows researchers to find the general region of the genome in which quantitative trait loci reside by using marker loci that are easily assayed, but unrelated to the trait in question, in order to identify the approximate locations of the unknown alleles that do affect the trait of interest. (From Bergstrom and Dugatkin, 2012)

FIGURE 4. 4. QTLs for mouse behavior FIGURE 4.4. QTLs for mouse behavior. Chromosomal distribution of QTLs linked to anxiety in mice. (From Wills-Owen and Flint, 2006)

FIGURE 4. 4. QTLs for mouse behavior FIGURE 4.4. QTLs for mouse behavior. Chromosomal distribution of QTLs linked to anxiety in mice. (From Wills-Owen and Flint, 2006)

FIGURE 4. 5. Foraging, age, and mRNA FIGURE 4.5. Foraging, age, and mRNA. (A) Foraging bees have significantly higher levels of per mRNA than younger, nonforaging bees. This difference could be due to age, behavior caste (forager versus nonforager), or both. (B) Some individual bees developed into precocious foragers that began searching for food much earlier than usual. When ten-day-old precocious foragers were compared with normal foragers (twenty-two-dayold foragers), Toma and his colleagues found no statistical differences in per mRNA levels. (From Toma et al., 2000)

FIGURE 4. 5a. Foraging, age, and mRNA FIGURE 4.5a. Foraging, age, and mRNA. (A) Foraging bees have significantly higher levels of per mRNA than younger, nonforaging bees. This difference could be due to age, behavior caste (forager versus nonforager), or both. (B) Some individual bees developed into precocious foragers that began searching for food much earlier than usual. When ten-day-old precocious foragers were compared with normal foragers (twenty-two-dayold foragers), Toma and his colleagues found no statistical differences in per mRNA levels. (From Toma et al., 2000)

FIGURE 4. 5b. Foraging, age, and mRNA FIGURE 4.5b. Foraging, age, and mRNA. (A) Foraging bees have significantly higher levels of per mRNA than younger, nonforaging bees. This difference could be due to age, behavior caste (forager versus nonforager), or both. (B) Some individual bees developed into precocious foragers that began searching for food much earlier than usual. When ten-day-old precocious foragers were compared with normal foragers (twenty-two-dayold foragers), Toma and his colleagues found no statistical differences in per mRNA levels. (From Toma et al., 2000)

FIGURE 4. 6. Pollen foragers, nectar foragers, and manganese FIGURE 4.6. Pollen foragers, nectar foragers, and manganese. Pollen foragers have more manganese in their heads than both nectar foragers and nurses. (From Ben-Shahar et al., 2004)

FIGURE 4. 7. A small change goes a long way FIGURE 4.7. A small change goes a long way. A single amino acid change is all that separates the coding for ultraviolet versus violet perception in the zebra finch. (Photo credit: Ann and Rob Simpson)

FIGURE 4. 8. FOXP2 and song learning FIGURE 4.8. FOXP2 and song learning. When the FOXP2 gene was knocked out in young zebra finches, their ability to learn other finches’ songs was diminished. (From Haesler et al., 2007)

FIGURE 4. 8. FOXP2 and song learning FIGURE 4.8. FOXP2 and song learning. When the FOXP2 gene was knocked out in young zebra finches, their ability to learn other finches’ songs was diminished. (From Haesler et al., 2007)

FIGURE 4. 9. ZENK and exposure to song FIGURE 4.9. ZENK and exposure to song. (A) Induction of zenk mRNA in the forebrain of a male zebra finch that has been exposed to zebra finch song for forty-five minutes. (B) Same area in male that was not exposed to song. (From Mello et al., 1992, p. 6819; courtesy Claudio Mello)

FIGURE 4. 10. Zenk levels and habituation FIGURE 4.10. Zenk levels and habituation. (A) Induced zenk mRNA levels decreased with increased exposure to the same song in male zebra finches. (B) Induced zenk mRNA levels increased when a male zebra finch was exposed to a new song. (Adapted from Mello et al., 1995)

FIGURE 4. 10. Zenk levels and habituation FIGURE 4.10. Zenk levels and habituation. (A) Induced zenk mRNA levels decreased with increased exposure to the same song in male zebra finches. (B) Induced zenk mRNA levels increased when a male zebra finch was exposed to a new song. (Adapted from Mello et al., 1995)

FIGURE 4. 10a. Zenk levels and habituation FIGURE 4.10a. Zenk levels and habituation. (A) Induced zenk mRNA levels decreased with increased exposure to the same song in male zebra finches. (B) Induced zenk mRNA levels increased when a male zebra finch was exposed to a new song. (Adapted from Mello et al., 1995)

FIGURE 4. 10b. Zenk levels and habituation FIGURE 4.10b. Zenk levels and habituation. (A) Induced zenk mRNA levels decreased with increased exposure to the same song in male zebra finches. (B) Induced zenk mRNA levels increased when a male zebra finch was exposed to a new song. (Adapted from Mello et al., 1995)

FIGURE 4. 10b. Zenk levels and habituation FIGURE 4.10b. Zenk levels and habituation. (A) Induced zenk mRNA levels decreased with increased exposure to the same song in male zebra finches. (B) Induced zenk mRNA levels increased when a male zebra finch was exposed to a new song. (Adapted from Mello et al., 1995)

FIGURE 4. 11. Gene expression levels change as songbirds sing FIGURE 4.11. Gene expression levels change as songbirds sing. Expression of some genes increases as zebra finches sing, while expression of others decreases. (From Warren et al., 2010)

FIGURE 4. 11. Gene expression levels change as songbirds sing FIGURE 4.11. Gene expression levels change as songbirds sing. Expression of some genes increases as zebra finches sing, while expression of others decreases. (From Warren et al., 2010)

FIGURE 4. 12a. Avpr1a length and behavior FIGURE 4.12a. Avpr1a length and behavior. (A) A schematic of the long and short avpr1a alleles and the expression of vasopressin receptors in the brain of prairie voles (differences in expression can be seen at the two red arrows). (B) Both male care of offspring and the strength of partner preference were greater in males who were homozygous for the longer avpr1a allele. (From Donaldson and Young, 2008; Hammock and Young, 2005)

FIGURE 4. 12b. Avpr1a length and behavior FIGURE 4.12b. Avpr1a length and behavior. (A) A schematic of the long and short avpr1a alleles and the expression of vasopressin receptors in the brain of prairie voles (differences in expression can be seen at the two red arrows). (B) Both male care of offspring and the strength of partner preference were greater in males who were homozygous for the longer avpr1a allele. (From Donaldson and Young, 2008; Hammock and Young, 2005)

FIGURE 4. 13. Dispersal strategies in Erigone altra FIGURE 4.13. Dispersal strategies in Erigone altra. These spiders use temperature as a development cue for when to use risky (ballooning) versus less risky (rappeling) dispersal strategies. (Photo credit: TDP Invertebrate Surveyors and Consultants, Trevor Pendleton)

FIGURE 4. 14. Temperature, learning, and egg laying FIGURE 4.14. Temperature, learning, and egg laying. Exposure to cold temperature (4° C for three weeks for larvae in group 1, 4° C for twelve weeks for larvae in group 2) during development had significant effects on a female wasp’s ability as an adult to discriminate between hosts of different quality. Larvae in group 3, which were continuously raised at normal temperatures of 24° C, did not experience these effects. Exposure to cold temperature also had a strong negative effect on the speed at which females learned to avoid already parasitized hosts, as they had to choose to lay their eggs in patches in which none of the hosts had been parasitized (left), half had been parasitized (center), or all had been parasitized (right). Orange circles indicate a parasitized host. (Based on van Baaren et al., 2005)

FIGURE 4.15. Amount of licking and grooming differed in one- versus two-parent nests. (A) In prairie voles, pups in the biparental (BP) treatment received more licking and grooming than pups in the single-mother (SM) treatment. (B) After they matured, females that were raised by a male and female (BP-reared) displayed more licking/grooming and pup care than females raised by only a female (SM-reared). These females also spent less time away from their pups than females raised by only a female. (From Ahem and Young, 2009)

FIGURE 4.15a. Amount of licking and grooming differed in one- versus two-parent nests. (A) In prairie voles, pups in the biparental (BP) treatment received more licking and grooming than pups in the single-mother (SM) treatment. (B) After they matured, females that were raised by a male and female (BP-reared) displayed more licking/grooming and pup care than females raised by only a female (SM-reared). These females also spent less time away from their pups than females raised by only a female. (From Ahem and Young, 2009)

FIGURE 4.15b. Amount of licking and grooming differed in one- versus two-parent nests. (A) In prairie voles, pups in the biparental (BP) treatment received more licking and grooming than pups in the single-mother (SM) treatment. (B) After they matured, females that were raised by a male and female (BP-reared) displayed more licking/grooming and pup care than females raised by only a female (SM-reared). These females also spent less time away from their pups than females raised by only a female. (From Ahem and Young, 2009)

FIGURE 4. 16. Nest building and experience in oldfield mice FIGURE 4.16. Nest building and experience in oldfield mice. The proportion of females that did not start building nests was lower in experienced females (green) versus inexperienced females (orange). Experienced females began to build nests sooner and built superior nests than inexperienced. (From Margulis et al., 2005)