. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. A. RESTING NUCLEUS CHROMOSOMES THREAD-LIKE AND SCATTERED THROUGH- OUT NUCLEUS, NOT VISIBLE AS DISTINCT CHROMOSOMES B. LEPTOTENE NUCLEUS CHROMOSOMES BECOME EVIDENT AS DISTINCT STRUCTURES NUCLEOLUS C ZYGOTENE (SYNAPTENE) NUCLEUS HOMOLOGOUS CHROMOSOMES BEGIN TO SYNAPSE,! E, UNITE IN PAIRS D PACHYTENE NUCLEUS CHROMOSOME PAIRS BECOME CLOSELY ASSOCIATED AND EACH PAIR SHORTENS AND APPEARS MUCH THICKER EACH"CHR0M0S0ME" IS MADE UP OF FOUR CHROMAT
. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. A. RESTING NUCLEUS CHROMOSOMES THREAD-LIKE AND SCATTERED THROUGH- OUT NUCLEUS, NOT VISIBLE AS DISTINCT CHROMOSOMES B. LEPTOTENE NUCLEUS CHROMOSOMES BECOME EVIDENT AS DISTINCT STRUCTURES NUCLEOLUS C ZYGOTENE (SYNAPTENE) NUCLEUS HOMOLOGOUS CHROMOSOMES BEGIN TO SYNAPSE,! E, UNITE IN PAIRS D PACHYTENE NUCLEUS CHROMOSOME PAIRS BECOME CLOSELY ASSOCIATED AND EACH PAIR SHORTENS AND APPEARS MUCH THICKER EACH"CHR0M0S0ME" IS MADE UP OF FOUR CHROMATIDS,! E . IT IS A TETRAD DUE TO THE FACT THAT EACH HOMOLOGOUS CHROMOSOME WHICH ENTERED INTO THE ORIGINAL UNION HAS DIVIDED LONGITUDINALLY INTO TWO CHROMATIDS E. DIPLOTENE NUCLEUS THE CHROMATIDS OF EACH TETRAD SHOW A REPULSION FOR EACH OTHER AND THE TETRAD AS A WHOLE BEGINS TO OPEN UP THE CHROMATIDS ALSO BECOME MORE ATTENUANT, PARTICULARLY IN THE OOCYTE WHERE THE NUCLEUS EN- LARGES AND FORMS THE GERMINAL VESICLE IN WHICH THERE IS A LARGE AMOUNT OF NUCLEAR SAP THE CHROMATIDS BECOME VERY LONG AND MAY SHOW LATERAL LOOPS. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Nelsen, Olin E. (Olin Everett), b. 1898. New York, Blakiston
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Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
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Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
