Chromosome structure and mutations
... Humans tolerate X chromosome aneuploidy because X inactivation compensates for dosage ...
... Humans tolerate X chromosome aneuploidy because X inactivation compensates for dosage ...
Condensin II Promotes the Formation of Chromosome Territories by
... larval central nervous system [19,20]. Polyploid-polytene chromosomes, such as those of the larval salivary gland, also exhibit features of the Rabl configuration [21], whereas spermatocytes have been shown to form non-Rabl, globular CTs in the G2-phase of meiosis I [22]. The polyploid nurse cells o ...
... larval central nervous system [19,20]. Polyploid-polytene chromosomes, such as those of the larval salivary gland, also exhibit features of the Rabl configuration [21], whereas spermatocytes have been shown to form non-Rabl, globular CTs in the G2-phase of meiosis I [22]. The polyploid nurse cells o ...
Abnormal anaphase resolution - Journal of Cell Science
... (Lehner and O’Farrell, 1989) and string (Edgar and O’Farrell, 1989; Jimenez et al., 1990), is required to regulate the length of G2 phase within these newly cellularized embryonic cells (Edgar and O’Farrell, 1990), whereas zygotic expression of cyclin A is needed for subsequent cell division (Lehner ...
... (Lehner and O’Farrell, 1989) and string (Edgar and O’Farrell, 1989; Jimenez et al., 1990), is required to regulate the length of G2 phase within these newly cellularized embryonic cells (Edgar and O’Farrell, 1990), whereas zygotic expression of cyclin A is needed for subsequent cell division (Lehner ...
Meiotic and Mitotic Recombination in Meiosis
... Drosophila suggested that BLM promotes synthesis-dependent strand annealing, probably by disrupting D-loops after repair DNA synthesis (Adams et al. 2003; McVey et al. 2004), an activity human BLM has been shown to have in vitro (van Brabant et al. 2000; Bachrati et al. 2006). Second, in vitro studi ...
... Drosophila suggested that BLM promotes synthesis-dependent strand annealing, probably by disrupting D-loops after repair DNA synthesis (Adams et al. 2003; McVey et al. 2004), an activity human BLM has been shown to have in vitro (van Brabant et al. 2000; Bachrati et al. 2006). Second, in vitro studi ...
Investigation 9: Genetic Variation
... genetics code. The alleles for legs are aa, the alleles for eye color are Ee, the alleles for fur pattern are FF, and the alleles for tail shape are tt. • The combination of alleles in an organism’s chromosomes is the organism’s genotype. The genotype lists the paired alleles that are particular to ...
... genetics code. The alleles for legs are aa, the alleles for eye color are Ee, the alleles for fur pattern are FF, and the alleles for tail shape are tt. • The combination of alleles in an organism’s chromosomes is the organism’s genotype. The genotype lists the paired alleles that are particular to ...
Sex chromosomes demonstrate complex evolutionary trajectories
... the putative avian sex determining gene DMRT1 is consistently within the nonrecombining region of the sex chromosomes avian sex chromosomes have suppressed recombination through a series of punctuated events (“strata”) with a gradient of ages, reflected by higher levels of sequence homology betw ...
... the putative avian sex determining gene DMRT1 is consistently within the nonrecombining region of the sex chromosomes avian sex chromosomes have suppressed recombination through a series of punctuated events (“strata”) with a gradient of ages, reflected by higher levels of sequence homology betw ...
Intriguing evidence of translocations in Discus fish
... S. aequifasciatus, S. discus and S. haraldi male and female gonadal cells at interphase and prophase I had no heteropicnotic regions that indicated the presence of sex chromatin (Figures 2a, b and c). The chromosomal behavior in some meiotic phases of S. aequifasciatus and S. haraldi was similar, bu ...
... S. aequifasciatus, S. discus and S. haraldi male and female gonadal cells at interphase and prophase I had no heteropicnotic regions that indicated the presence of sex chromatin (Figures 2a, b and c). The chromosomal behavior in some meiotic phases of S. aequifasciatus and S. haraldi was similar, bu ...
Classical Genetics
... a. Because homologous pairs separate during meiosis, a gamete has only one allele from each pair of alleles. b. Read slide c. Could be disease-causing gene, causing dental/ocular disease, can follow that One-Trait Crosses and Probability [S15] a. Laws of probability alone can be used to determine re ...
... a. Because homologous pairs separate during meiosis, a gamete has only one allele from each pair of alleles. b. Read slide c. Could be disease-causing gene, causing dental/ocular disease, can follow that One-Trait Crosses and Probability [S15] a. Laws of probability alone can be used to determine re ...
The Chromosomal Basis of Inheritance
... laboratory began using this convenient organism for genetic studies in 1907 and soon became known as “the fly room.” Another advantage of the fruit fly is that it has only four pairs of chromosomes, which are easily distinguishable with a light microscope. There are three pairs of autosomes and one pa ...
... laboratory began using this convenient organism for genetic studies in 1907 and soon became known as “the fly room.” Another advantage of the fruit fly is that it has only four pairs of chromosomes, which are easily distinguishable with a light microscope. There are three pairs of autosomes and one pa ...
LINKAGE AND MAPPING IN EUKARYOTES
... gories in very high frequency have the same phenotypes as the original parents in the cross (P1 of fig. 6.2). That is, banded flies and detached flies were the original parents as well as the great majority of the testcross offspring. We call these phenotypic categories parentals, or nonrecombinants ...
... gories in very high frequency have the same phenotypes as the original parents in the cross (P1 of fig. 6.2). That is, banded flies and detached flies were the original parents as well as the great majority of the testcross offspring. We call these phenotypic categories parentals, or nonrecombinants ...
UNIT 1: INTRODUCTION TO BIOLOGY
... long DNA fragment as part of the total cellular DNA (=genome) that heavily folds and coils up into the typical X-shaped and visible chromosome form during cell division and meiosis every biological organisms has its genomic DNA fragmented into a definite number of chromosomes the otherwise non ...
... long DNA fragment as part of the total cellular DNA (=genome) that heavily folds and coils up into the typical X-shaped and visible chromosome form during cell division and meiosis every biological organisms has its genomic DNA fragmented into a definite number of chromosomes the otherwise non ...
Fine mapping of re-arranged Y chromosome in three infertile
... karyotype showed a mosaicism, including a 45,X cell line and a 46,X,i(Y)(p10). The AZF STS analysis on their buccal cells showed that a part of the long arms of the Y chromosome was actually present on the ‘isochromosome’ of both patients, since all AZFa markers were positive. However the AZFb þ c m ...
... karyotype showed a mosaicism, including a 45,X cell line and a 46,X,i(Y)(p10). The AZF STS analysis on their buccal cells showed that a part of the long arms of the Y chromosome was actually present on the ‘isochromosome’ of both patients, since all AZFa markers were positive. However the AZFb þ c m ...
PUNNETT SQUARE PROBLEMS (or how to do a cross): STEP 1
... can produce When you are doing a monohybrid cross, finding possible gametes is easy. All you have to do is give one allele to half the gametes, and the other allele to the other half of the gametes (remember gametes are haploid, so they get only 1 of each gene or letter!). Then cross out any duplica ...
... can produce When you are doing a monohybrid cross, finding possible gametes is easy. All you have to do is give one allele to half the gametes, and the other allele to the other half of the gametes (remember gametes are haploid, so they get only 1 of each gene or letter!). Then cross out any duplica ...
chromosomal
... ~ 92 % of cases are numerical: trisomy 21 KARYOTYPE: 47,XX,+21 or 47,XY,+21 In 90 % in trisomy 21 additional chromosome comes from the mother’s egg [error in oogenesis: maternal non-disjunction meiosis I ] ...
... ~ 92 % of cases are numerical: trisomy 21 KARYOTYPE: 47,XX,+21 or 47,XY,+21 In 90 % in trisomy 21 additional chromosome comes from the mother’s egg [error in oogenesis: maternal non-disjunction meiosis I ] ...
Meiosis: Its Origin According to the Viral
... either ancestor alone. A classic example is that of lichens, which are composed of a photobiont (cyanobacteria or alga) and a fungal host that have co-evolved to such an extent they are classified as ''lichen'' species, despite the fact that each lichen consists of at least two separate organisms th ...
... either ancestor alone. A classic example is that of lichens, which are composed of a photobiont (cyanobacteria or alga) and a fungal host that have co-evolved to such an extent they are classified as ''lichen'' species, despite the fact that each lichen consists of at least two separate organisms th ...
Lethal Mutations and Balanced Lethal Systems in
... assumption that the frequency of lethals is the same for all chromosomes-an assumption unlikely to be fully justified-the lethal frequency for the whole genome was between 24 yoand 32 %. This agrees well with the 25 yo found by Kafer & Chen (1964) under similar conditions. Despite an intensive inves ...
... assumption that the frequency of lethals is the same for all chromosomes-an assumption unlikely to be fully justified-the lethal frequency for the whole genome was between 24 yoand 32 %. This agrees well with the 25 yo found by Kafer & Chen (1964) under similar conditions. Despite an intensive inves ...
Bio 100 Placement Study Guidelines
... 6.! Explain how cloning is different from sexual reproduction. 7.! Describe how gene probes help biologists locate specific DNA sequences. 8.! Compare and contrast preimplantation genetic diagnosis, genetic testing, and gene therapy. 9.! Identify ethical issues associated with the use of DNA technol ...
... 6.! Explain how cloning is different from sexual reproduction. 7.! Describe how gene probes help biologists locate specific DNA sequences. 8.! Compare and contrast preimplantation genetic diagnosis, genetic testing, and gene therapy. 9.! Identify ethical issues associated with the use of DNA technol ...
Independent Assortment of Genes
... c. To find a formula for the number of genotypes, first consider the following: Number of genes ...
... c. To find a formula for the number of genotypes, first consider the following: Number of genes ...
GENETICS accepted
... a total RNA concentration of 20ng/µl into one day old adult worms which were transferred every 24 hours for 3 days to new plates. The presence of male progeny was assessed 3-5 days later. A subset of F1 progeny was also individually plated to determine whether broods contained males. from both the P ...
... a total RNA concentration of 20ng/µl into one day old adult worms which were transferred every 24 hours for 3 days to new plates. The presence of male progeny was assessed 3-5 days later. A subset of F1 progeny was also individually plated to determine whether broods contained males. from both the P ...
Multiple Barriers to Nonhomologous DNA End Joining
... Surprisingly, the triple mutants also produced a low frequency of ventralized embryos, indicating the DSB repair checkpoint is suppressed despite the persistence of unrepaired DSBs (Table 2). Thus, an alternative explanation for the suppression of eggshell phenotypes in the triple mutants is that ME ...
... Surprisingly, the triple mutants also produced a low frequency of ventralized embryos, indicating the DSB repair checkpoint is suppressed despite the persistence of unrepaired DSBs (Table 2). Thus, an alternative explanation for the suppression of eggshell phenotypes in the triple mutants is that ME ...
Standards: 7-2
... 1. Prepare a clean slide with 2-3 drops of 0.7% NaCl (saline) and put the slide (without a cover slip) on a stereoscopic (dissecting) microscope. 2. Select a large Drosophila melanogaster larva and place it on the slide. 3. While looking through the microscope use probes or forceps to grasp the larv ...
... 1. Prepare a clean slide with 2-3 drops of 0.7% NaCl (saline) and put the slide (without a cover slip) on a stereoscopic (dissecting) microscope. 2. Select a large Drosophila melanogaster larva and place it on the slide. 3. While looking through the microscope use probes or forceps to grasp the larv ...
FtsK-Dependent Dimer Resolution on Multiple Chromosomes
... chromosome with dif located at the junction of their polarity [22,23]. Thus, dif sites carried by a dimer are brought together by FtsK translocation (Figure 1A). Second, FtsK serves to activate recombination at dif via a direct interaction with XerD [24,25]. dif contains two 11bp binding sites for X ...
... chromosome with dif located at the junction of their polarity [22,23]. Thus, dif sites carried by a dimer are brought together by FtsK translocation (Figure 1A). Second, FtsK serves to activate recombination at dif via a direct interaction with XerD [24,25]. dif contains two 11bp binding sites for X ...
10 m
... microtubules and associated proteins It controls chromosome movement during mitosis In animal cells, assembly of spindle microtubules begins in the centrosome, a type of microtubule organizing center ...
... microtubules and associated proteins It controls chromosome movement during mitosis In animal cells, assembly of spindle microtubules begins in the centrosome, a type of microtubule organizing center ...
Production of Diploid Male Gametes in Arabidopsis
... Whole-genome duplication through the formation of diploid gametes is a major route for polyploidization, speciation, and diversification in plants. The prevalence of polyploids in adverse climates led us to hypothesize that abiotic stress conditions can induce or stimulate diploid gamete production. ...
... Whole-genome duplication through the formation of diploid gametes is a major route for polyploidization, speciation, and diversification in plants. The prevalence of polyploids in adverse climates led us to hypothesize that abiotic stress conditions can induce or stimulate diploid gamete production. ...
Chapter 15
... If these two genes were on different chromosomes, the alleles from the F1 dihybrid would sort into gametes independently, and we would expect to see equal numbers of the four types of offspring. If these two genes were on the same chromosome, we would expect each allele combination, B+ vg+ and b vg, ...
... If these two genes were on different chromosomes, the alleles from the F1 dihybrid would sort into gametes independently, and we would expect to see equal numbers of the four types of offspring. If these two genes were on the same chromosome, we would expect each allele combination, B+ vg+ and b vg, ...
Meiosis
Meiosis /maɪˈoʊsɨs/ is a specialized type of cell division which reduces the chromosome number by half. This process occurs in all sexually reproducing single-celled and multi-celled eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as meiosis I and meiosis II. Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids. In meiosis I, homologous chromosomes pair with each other and can exchange genetic material in a process called chromosomal crossover. The homologous chromosomes are then segregated into two new daughter cells, each containing half the number of chromosomes as the parent cell. At the end of meiosis I, sister chromatids remain attached and may differ from one another if crossing-over occurred. In meiosis II, the two cells produced during meiosis I divide again. Sister chromatids segregate from one another to produce four total daughter cells. These cells can mature into various types of gametes such as ova, sperm, spores, or pollen.Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization) to form a zygote with a complete chromosome count containing a combination of paternal and maternal chromosomes. Thus, meiosis and fertilization facilitate sexual reproduction with successive generations maintaining the same number of chromosomes. For example, a typical diploid human cell contains 23 pairs of chromosomes (46 total, half of maternal origin and half of paternal origin). Meiosis produces haploid gametes with one set of 23 chromosomes. When two gametes (an egg and a sperm) fuse, the resulting zygote is once again diploid, with the mother and father each contributing 23 chromosomes. This same pattern, but not the same number of chromosomes, occurs in all organisms that utilize meiosis. Thus, if a species has 30 chromosomes in its somatic cells, it will produce gametes with 15 chromosomes.