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Meiosis figure

Figure 1. Expression of c-mos in mouse oocytes, c-mos is transcribed during oocyte growth and transcripts with short poly(A) tails are accumulated in fully-grown germinal vesicle (GV) stage oocytes. These transcripts are polyadenylated and translated following the resumption of meiosis and then degraded following fertilization and cleavage to the two-cell stage. Figure 1. Expression of c-mos in mouse oocytes, c-mos is transcribed during oocyte growth and transcripts with short poly(A) tails are accumulated in fully-grown germinal vesicle (GV) stage oocytes. These transcripts are polyadenylated and translated following the resumption of meiosis and then degraded following fertilization and cleavage to the two-cell stage.
Figure 2. Role of c-mos in meiosis of mouse oocytes. Mouse oocytes microinjected with antisense c-mos oligonucleotides fail to progress from meiosis I to meiosis II, instead reforming nuclei following polar body extrusion (O Keefe et al., 1989). Figure 2. Role of c-mos in meiosis of mouse oocytes. Mouse oocytes microinjected with antisense c-mos oligonucleotides fail to progress from meiosis I to meiosis II, instead reforming nuclei following polar body extrusion (O Keefe et al., 1989).
Figure 1-4-3. Large Segment Deletion During Crossing-Over In Meiosis... Figure 1-4-3. Large Segment Deletion During Crossing-Over In Meiosis...
Proliferation of spermatocytes by meiosis, in which the number of chromosomes is halved. The process of meiosis is discussed in Chapter 20, where it can be compared with mitosis (Figure... [Pg.430]

The first cell division of meiosis occurs in the primary oocyte but the process is arrested during prophase and remains so until puberty. Just before ovulation, meiosis, which has been arrested since before birth, resumes. The first division halves the number of chromosomes to produce the haploid secondary oocyte. The process is the same as that in spermatozoa (Chapter 20 see Figure 20.29 ) except that the two resulting haploid daughter cells are unequal in size. One is the large functional secondary oocyte whereas the other is much smaller and is known as the first polar body. The second meiotic division is arrested at metaphase. It is completed only at fertilisation. Once again, the division is unequal. One cell is large, the secondary oocyte. The other is small, a second polar body, which is discarded. [Pg.434]

The first division of meiosis results in two daughter cells, each of which contains one complete (haploid) set of chromosomes. The second division of meiosis (which follows the same course as mitosis) results in these two cells becoming four, each of which can develop into a gamete (Figure 20.29). [Pg.472]

Figure 6.45 Crossover at meiosis. Two homologous chromosomes are shown aligned in the top line. Each consists of two chromatids, joined together at the centromere. A and B represent genes on one chromosome, and a and b the corresponding alleles on the other chromosome. After recombination two new gene combinations are apparent. The middle and bottom lines represent other possible methods of recombination. Source From Refs. 12 and 13. Figure 6.45 Crossover at meiosis. Two homologous chromosomes are shown aligned in the top line. Each consists of two chromatids, joined together at the centromere. A and B represent genes on one chromosome, and a and b the corresponding alleles on the other chromosome. After recombination two new gene combinations are apparent. The middle and bottom lines represent other possible methods of recombination. Source From Refs. 12 and 13.
A likely pathway for homologous recombination during meiosis is outlined in Figure 25-31a. The model has four key features. First, homologous chromosomes are aligned. Second, a double-strand break in a DNA mole-... [Pg.980]

Figure 26-12 Meiosis. Cell division leading to formation of haploid gametes. Figure 26-12 Meiosis. Cell division leading to formation of haploid gametes.
Oogenesis (the process that produces mature ova) begins at puberty in mammalian females (Figure 2). Note that the series of mitoses of oogonial cells occurs only in utero-, all the primary oocytes a female will have ( 500 000 in humans, most of which will die) are present in her ovaries prior to her birth. In utero, each primary oocyte proceeds through the second (of four) phases of meiosis I and waits until puberty and the onset of the cyclical release of FSH... [Pg.2692]

Figure 23. Proteins with known functionalities. 1, metalloproteases 2, meiosis/mitochondria 3, secretion/neurotransmission 5, cell division cycle/centrosome/ER homotypic fusion 6-9, subunits of the 26S proteasome (s4 6, s6 7, s7 8, s8 9) Configurations are the same as those shown in Fig. 22, but proteins without known functionalities are omitted. Figure 23. Proteins with known functionalities. 1, metalloproteases 2, meiosis/mitochondria 3, secretion/neurotransmission 5, cell division cycle/centrosome/ER homotypic fusion 6-9, subunits of the 26S proteasome (s4 6, s6 7, s7 8, s8 9) Configurations are the same as those shown in Fig. 22, but proteins without known functionalities are omitted.
Figure 40-7 Schematic representation of the CGG repeat in exon I of FAIR/ and associated alleles. A CGG-repeat number less than or equal to 45 Is normal. A CGG-repeat number of 46 to 54 is in the gray zone and has been reported to expand to a full mutation in some families. A CGG-repeat number of 55 to 200 is considered a premutation allele and is prone to expansion to a full mutation during female meiosis. A CGG-repeat number in excess of 200 is considered a full mutation and is diagnostic of fragile X syndrome. Figure 40-7 Schematic representation of the CGG repeat in exon I of FAIR/ and associated alleles. A CGG-repeat number less than or equal to 45 Is normal. A CGG-repeat number of 46 to 54 is in the gray zone and has been reported to expand to a full mutation in some families. A CGG-repeat number of 55 to 200 is considered a premutation allele and is prone to expansion to a full mutation during female meiosis. A CGG-repeat number in excess of 200 is considered a full mutation and is diagnostic of fragile X syndrome.
A FIGURE 1-18 Dad made you a boy or girl. In animals, meiosis of diploid precursor cells forms eggs and sperm (gametes). The male parent produces two types of sperm and determines the sex of the zygote. In humans, as shown here, X and Y are the sex chromosomes the zygote must receive a Y chromosome from the male parent to develop into a male. A=autosomes (non-sex chromosomes). [Pg.18]

A FIGURE 9-45 Recombination during meiosis. (a) Crossing over can occur between chromatids of homologous chromosomes before the first meiotic division (see Figure 9-3). [Pg.396]

Most satellite DNA is composed of repeats of 14-500 base pairs in tandem repeats of 20-100 kb. In situ hybridization studies with metaphase chromosomes have localized these satellite DNAs to specific chromosomal regions. In most mammals, much of this satellite DNA lies near centromeres, the discrete chromosomal regions that attach to spindle microtubules during mitosis and meiosis. Satellite DNA is also located at telomeres, the ends of chromosomes, and at specific locations within chromosome arms in some organisms. These latter sequences can be useful for identifying particular chromosomes by fluorescence in situ hybridization (FISH), as Illustrated in Figure 10-5. [Pg.413]

The length of a particular simple-sequence tandem array is quite variable between individuals in a species, probably because of unequal crossing over during meiosis (see Figure... [Pg.414]


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