Group items tagged

In this clicker case study for a flipped classroom, students familiar with the stages of meiosis work in small groups to determine the predicted genetic makeup of the parthenogenetic offspring of a Komodo dragon, based on four different types of parthenogenesis. Students then learn about the actual genetic makeup of the offspring and determine how meiosis was modified to allow parthenogenesis in this fascinating lizard. The sex of the offspring is explained, based on ZW/ZZ sex determination. A video specifically made for this case prepares students for the in-class activities, which are guided by a PowerPoint presentation. The case also examines how facultative parthogenesis may be adaptive in Komodo dragons and the implications of facultative parthogenesis to conservation of these vulnerable lizards. The case was developed for a general biology class, but could also be used in an introductory course on conservation or cell biology.

This initial module from the GENIQUEST project introduces the dragons and the inheritance of their traits, then delves into meiosis and its relationship to inherited traits. Students examine the effects of choosing different gametes on dragon offspring, and learn about genetic recombination by creating recombination events to generate specific offspring from two given parent dragons. Students learn about inbred strains and breed an inbred strain of dragons themselves. Lastly, students investigate a mysterious new dragon trait and use the properties of linkage and inheritance to examine the trait's relationship to other, known dragon traits.

ach of the four hallmarks of autosomal dominant inheritance are fulfilled. Each affected individual has an affected parent; there is no skipping of generations. Males and females are equally likely to be affected. About 1/2 of the offspring of an affected individual are affected (the recurrence risk is 1/2). Normal siblings (II-3) of affected individuals have all normal offspring.

An innovative new breeding simulation helps reveal genetic ratios in offspring. With the heredity level of the ConnectedBio Multi-Level Simulation (MLS), students breed pairs of mice with different fur colors and observe the phenotypic ratios in the resulting offspring. The goal of this activity is to demystify the science behind Punnett Squares and encourage students to explore data and statistical representations in genetics and heredity.

In a retrospective cohort study investigating the role of epigenetic control in the onset of allergic diseases, it was shown that mothers who suffered from allergic symptoms very early in pregnancy were more likely to have offspring with allergies. This was compared to mothers who did not suffer from allergies in early pregnancy, taking into account family history of allergies and total allergic response during pregnancy (10). These results indicate that gene-environment interactions during embryonic development may modify the epigenetic code in ways that may potentially lead to allergic disease.

After an exhaustive survey of contemporary epigenetics studies, one researcher has concluded that some of the effects of stress, cancer and other chronic diseases may be passed on to our offspring -- and theirs -- through deep and complicated underlying cellular mechanisms that scientists are just beginning to understand.

The external environment's effects upon genes can influence disease, and some of these effects can be inherited in humans. Studies investigating how environmental factors impact the genetics of an individual's offspring are difficult to design. However, in certain parts of the world in which social systems are highly centralized, environmental information that might have influenced families can be obtained. For example, Swedish scientists recently conducted investigations examining whether nutrition affected the death rate associated with cardiovascular disease and diabetes and whether these effects were passed from parents to their children and grandchildren (Kaati et al., 2002). These researchers estimated how much access individuals had to food by examining records of annual harvests and food prices in Sweden across three generations of families, starting as far back as the 1890s. These researchers found that if a father did not have enough food available to him during a critical period in his development just before puberty, his sons were less likely to die from cardiovascular disease. Remarkably, death related to diabetes increased for children if food was plentiful during this critical period for the paternal grandfather, but it decreased when excess food was available to the father. These findings suggest that diet can cause changes to genes that are passed down though generations by the males in a family, and that these alterations can affect susceptibility to certain diseases. But what are these changes, and how are they remembered? The answers to questions such as these lie in the concept of epigenetics.

Researchers at the University of Pennsylvania performed "stress tests" on pregnant mice using a predator's odor, restraint, or unfamiliar noises. After the mice gave birth, the scientists analyzed the bacterial communities in their vaginas and in their pups' colons. The researchers found that stress during pregnancy altered the expression levels of several proteins involved in vaginal immunity and the frequency of Lactobacillus bacteria, which, expectedly, correlated to lower frequencies of Lactobacillus within their pups' gut microbiomes. Male pups of stressed mothers also displayed an increase in anaerobic bacteria like Clostridium and Bacteroidesin.

Like many newborn mammals, baby mice cry to get their mother's attention. But the mother doesn't instinctively recognize these calls; she must learn the sounds of her offspring-just as human parents must learn the cries of their infants. Now, a team of researchers has discovered that the hormone oxytocin, which has been tied to trust and maternal bonding, holds the key to how this learning occurs. Only after oxytocin  tweaks the brain of a female mouse does she respond with a mother's concern and attentiveness to crying pups.

Malaria has long been a problem in Mali. But in 2006, the situation got worse: a malaria-carrying mosquito species named Anopheles coluzzii became increasingly resistant to common insecticides. Scientists searched for an explanation in its genes. Somehow, the species had acquired mutations that were previously only found in another species, Anopheles gambiae - despite the fact that these two species didn't usually mate with each other, and that their hybrids tended to die without producing offspring of their own, the mutations were identical.

Your mother's DNA may have determined your eye color, but some traits that you thought came from her may instead have come from the DNA of bacteria she passed on to you soon after birth, a new study finds. The study found that a mother mouse can pass along to her offspring a susceptibility to intestinal disorders, such as inflammatory bowel disease, by way of a gut-residing bacterium called Sutterella, the researchers reported in the journal Nature on Feb. 16.

In most animals, the drive to breed and produce offspring is strong. However, most males live their whole lives without having the chance to breed. The events leading up to mating can be very dangerous and also very costly to an individual. Some males have evolved elaborate structures, or weapons, as a result. The structures do help males in both combative situations and with attracting females, but ironically, the structures themselves come with certain costs. This flipped case study provides students with the opportunity to not only see how animal structures and functions are linked, but also to see how certain animal structures are needed and costly. There are videos that students are expected to view before the case. The case was initially designed for a second semester college general biology class for majors. However, it can also be used in non-major biology classes. Students should have some background knowledge of natural selection, specifically sexual selection as well as energetic demands of certain structures.

Men, your sperm know how heavy you are. A new study reveals that sperm carry different chemical tags on their DNA depending on whether their owner is lean or obese. The findings suggest that men may be able to pass information about the availability of food in their environment down to their offspring, which could influence their child's odds of being overweight.

If the lab technique works in the field, it could offer a new way of stopping the biting insects from spreading malaria to humans, they say. The scientists put a new "resistance" gene into the mosquito's own DNA, using a gene editing method called Crispr. And when the GM mosquitoes mated - their offspring inherited the same resistance, PNAS journal reports. In theory, if these mosquitoes bite people, they should not be able to pass on the parasite that causes malaria.

Now, a new study reports that at least one species of songbird-and likely many more-already knows how to prep its chicks for a warming world. They do so by emitting special calls to the embryos inside their eggs, which can hear and learn external sounds. This is the first time scientists have found animals using sound to affect the growth, development, behavior, and reproductive success of their offspring, and adds to a growing body of research revealing that birds can "doctor" their eggs.

Hybrid animals are infertile because of the way their sex cells form. But sometimes, life finds a way.