Talk:2009 Group Project 2

Hallo group 2

Being that I have no idea who you all are, let me introduce myself, I am Mitchell.

As for our little topic, what does everyone think about what we should choose?

Personally, I think Guinea Pig and Rat will obviously have the most information available, but obviously everyone is thinking the same, so it might not be available. The others should be interesting, but it would be challenging to find much information on them.

Thoughts??

Hi

I don't mind which species we choose.......I think we discuss it more in class on thursday

)

Helpful links: http://embryology.med.unsw.edu.au/Otheremb/Fly.htm

http://embryology.med.unsw.edu.au/Movies/fly.htm

http://people.ucalgary.ca/~browder/virtualembryo/flies.html

http://www.medicalnewstoday.com/articles/131669.php

http://biology.kenyon.edu/courses/biol114/Chap13/Chapter_13A.html

http://www.sdbonline.org/fly/atlas/00atlas.htm

http://www.sdbonline.org/fly/aimain/1aahome.htm

http://www.sdbonline.org/fly/aimain/2stages.htm

I have also found that the 'Biology' 3rd edition by Knox textbook is fairly amazing, at least for the stages. Could be good for some inspiration??

Juls -  Timeline of Development - how long

    Mitchell - Staging - are there species specific staging, what occurs when

      Carly  - History of Model Use - when was it first used, what embryology research

        Tom  - Genetics - chromosome number, sequencing

Group Effort - Current Embryology Research - research papers and findings

Tom's notes:

http://www.yale.edu/ynhti/curriculum/units/1996/5/96.05.01.x.html

http://www.accessexcellence.org/AE/AEPC/WWC/1994/genentics.php

http://books.google.com.au/books?id=CgtIr1V0zxAC&printsec=frontcover&dq=drosophila+genetics&source=gbs_similarbooks_r&cad=3#v=onepage&q=&f=false

http://www.ncbi.nlm.nih.gov/mapview/draw_chr.cgi?chr=X/21591800/2L/22678900/2R/21288900/3L/24978000/3R/29717200/4/1395140/!Y/2754000/!MT//&links=off

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=genomeprj&Cmd=Retrieve&list_uids=29999

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=genome&Cmd=ShowDetailView&TermToSearch=10015

For Carly http://www.ncbi.nlm.nih.gov/pubmed/10731135?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=4&log$=relatedarticles&logdbfrom=pubmed

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This is what I have written so far in terms of stages. I have not yet proof read it, that will be for tomorrow morning en-route to lab :) Tell me what you think. --Mitchell Mathieson 19:31, 19 August 2009 (EST)

Stage 1

0hr - 0:25hr first 2 nuclear divisions. Dark in center, lighter at periphery. Center contains yolk granules distributed evenly throughout

Stage 2

0:25hr - 1:5hr syncytial divisons 2-8, retraction of egg cytoplasm, separating from vitelline envelope. Leads to appearance of two empty spaces at anterior and posterior poles

Stage 3

1:5hr - 1:20hr syncytial divion 9, polar bud formation; budding off of 2 protuberances, at end of 8th syncytial division, into cleft at posterior pole, divide once. Appearance of cytoplasmic periphery indicates end of stage

Stage 4

1:20hr-2:10hr syncytial divions 10-13, pole cell formation in posterior space. greatly increased number of polar buds which become pole cells. Blastoderm nuclei are discernible

Stage 5

2:10hr-2:50hr cellularization. Pole cells begin moving dorsally. Blastoderm cell formation, nuclei elongate. Anterior space disappears

Stage 6

2:50hr-3:00hr onset of gastrulation, formation of ventral and cephalic furrow, dorsal shift of pole cells. Mesodermal and endodermal originate at ventral furrow, and then start to invaginate. Blastoderm cells at posterior pole shift position to form dorsal plate, where pole cells adhere/ cephalic furrow visible at 2/3rd embryo length. Ventral furrow continues extending until it covers almost entire length of embryo

Stage 7

3:00hr-3:10hr Begins when cell plate at the posterior pole reaches a horizontal orientation. Completion of gastrulation; endoderm primordia of anterior and posterior midgut and the primordium of the hindgut invaginate. As a result, three dorsal folds become clearly visible diverging in a dorsoventral direction. The cephalic furrow is a deep invagination, persisting until stage 9, whereas the anterior transversal fold and posterior transversal fold are superficial and short lasting. Most of the cells comprising the latter two folds are made up of extraembryonic membrane. The invagination of the cell plate and pole cells forms the posterior midgut. Pole cells are no longer visible unless viewed by histological sectioning and examination. Cells caudal to invaginating midgut surround the superficial opening of the midgut, forming a neck of cells, which become the hindgut.

Stage 8

3:10hr-3:40hr Beginning of stage signified by formation of amnioproctodeal invagination, and the rapid phase of germ band expansion to 60% egg length. At the end of germ band expansion the proctodeal opening is located at about 60% embryo length. The germ bands are consisting of an mesodermal layer on the inside, and an ectodermal layer on the exterior, which are almost indistinguishable. At this point, the cells remaining on the outer surface of the embryo form the ectoderm and amnioserosa.

Stage 9

3:40hr-4:20hr First neuroblasts delaminate from ectoderm giving a clearly demarcated layering to the germ band; mesoderm-neuroblasts-outer ectoderm. Anterior pole separates from vitelline envelope through ventral retraction. This gives rise to stomodeal cell plate, which begins to invaginate at the end of stage 9. Germ band expansion continues.

Stage 10

4:20hr-5:20hr Stomodeum invaginates, which forms foregut. Stomodeal plate cells divide mitotically, and form a regular single layered epithelium which tilts posteriorly, establishing contact with the cell mass of anterior midgut primordium. Germ band expansion reaches maximum length at 75% of embryo length. Pole cells leave posterior midgut, and come to rest on both sides of posterior midgut outside yolk sac. Parasegmental grooves appear in epidermis of the trunk.

Stage 11

5:20-7:20hr Stage ends at first signs of germ band retraction. Segmental furrows apparent. Ten tracheal pits arise, with the anterior most pits opening into the 1st and 2nd thoracic segment boundary, giving rise to anterior spiracles. Posterior most pits open into 8th abdominal segment, forming posterior spiracles. Remaining pits grow and fuse to form tracheal tree. Posterior midgut invagination bends ventrally to reach posterior pole. Malpighian tubules form as two buds at the junction of posterior midgut and hindgut. Apoptosis also begins in this stage.

Stage 12

7:20hr-9:20hr Germ bands start retracting caudally. While the germ band length is decreasing, the width increases one and a half times. Anterior midgut and posterior midgut fuse together. Yolk sac is moved to dorsal embryo, and retracts from cephalic regions. It is covered by amnioserosa. Three invaginations form on the roof of the foregut, which precede the development of stomatogastric nervous system. Tracheal tubes start to fuse. The ventral cord separates from epidermis.

Stage 13

9:20hr-10:20hr Stage 13 commences with the completion of germ band shortening. At this point the anal plate occupies posterior pole. The head of the embryo begins to involute. A triangular gap begins to form ventrally at the anterior pole as a result of the clypeolabrum becoming thinner and beginning to retract. The labium moves to the midline on the ventral side. The yolk sac begins to protrude dorsally, becoming convex in shape.

Stage 14

10:20hr-11:20hr Head continues involution. The dorsum of the embryo begins closing, as does the midgut. The labium moves inwardly, followed by the opening of the salivary glands into the mouth. The dorsal spiracles become evident.

Stage 15

12:20hr-13:00hr Dorsal closure of epidermis, and closure of the gut, with the gut completely containing the yolk sac. Completion of epidermal segmentation occurs. Dorsal ridge reaches 85% embryo length. Condensation of nerve cord initiates. Involution of head continues

Stage 16

13:00hr-16:00hr Stage begins once intersegmental grooves are distinguishable at middorsal levels. The stage ends with the dorsal ridge overgrowing the top of the clypeolabrum, including it in the atrium. Cuticle begins to be secreted in the epidermis, tracheal tree and foregut and hindgut. Somatic musculature and sensory organs become visible, and heart forms a mid-dorsal position. Four gastric caecae evaginate from the midgut. Proventriculus demarcates foregut/midgut junction

Stage 17

Continues until hatching of embryo Air starts to infiltrate the tracheal tree. Ventral cord continues to retract. Embryo begins to move within Vitelline envelope. There is no clear difference between stages 16 and 17.

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