1 / 11

Heredity, Gene Regulation, and Development I. Mendel's Contributions

Explore Mendel's contributions, meiosis and the chromosomal theory, allelic, genic, and environmental interactions, and sex determination and sex linkage in this comprehensive study of heredity, gene regulation, and development.

paniagua
Download Presentation

Heredity, Gene Regulation, and Development I. Mendel's Contributions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Heredity, Gene Regulation, and Development I. Mendel's Contributions II. Meiosis and the Chromosomal Theory III. Allelic, Genic, and Environmental Interactions IV. Sex Determination and Sex Linkage

  2. Heredity, Gene Regulation, and Development • I. Mendel's Contributions • II. Meiosis and the Chromosomal Theory • III. Allelic, Genic, and Environmental Interactions • IV. Sex Determination and Sex Linkage • A. Sex Determination • Environmental Sex Determination • a. Temperature MT FT

  3. Heredity, Gene Regulation, and Development • I. Mendel's Contributions • II. Meiosis and the Chromosomal Theory • III. Allelic, Genic, and Environmental Interactions • IV. Sex Determination and Sex Linkage • A. Sex Determination • Environmental Sex Determination • a. Temperature MT FT

  4. A. Sex Determination • Environmental Sex Determination • a. Temperature • b. Size/Nutrition Arisaema triphyllum “Jack-in-the-Pulpit” Small plants - male Large plants - female

  5. A. Sex Determination • Environmental Sex Determination • a. Temperature • b. Size/Nutrition • c. Social Environment Sexually mature female (Inhibits development of males) Sexually mature male Immature males Wouldn’t the species do better if there were more females/group? Yes, but selection favors individual reproductive success.

  6. A. Sex Determination • Environmental Sex Determination • Chromosomal Sex Determination • a. Protenor sex determination The presence of 1 or 2 sex chromosomes determines sex Order: Hemiptera “True Bugs” Family Alydidae – Broad-headed bugs

  7. A. Sex Determination • Environmental Sex Determination • Chromosomal Sex Determination • a. Protenor sex determination • b. Lygaeus sex determination The type of sex chromosomes determines sex Order: Hemiptera Family: Lygaeidae “Chinch/Seed Bugs”

  8. A. Sex Determination • Environmental Sex Determination • Chromosomal Sex Determination • a. Protenor sex determination • b. Lygaeus sex determination • c. In humans: the sry gene The sry gene (sex-determining region of the Y) codes for a transcription factor – a protein that binds to DNA and turns other genes on. The genes that are turned on cause the gonad to develop into a testis and begin secreting testosterone, causing the embryo to develop into a male. Though rare, crossing-over between the X and Y chromosomes in males can produce Y’s that LACK sry and X’s that HAVE IT. If these gametes fertilize an egg, XX males and XY females are produced.

  9. A. Sex Determination • Environmental Sex Determination • Chromosomal Sex Determination • a. Protenor sex determination • b. Lygaeus sex determination Which sex is the ‘heterogametic’ sex varies XX female, XY – male Most mammals, including humans Some insects Some plants ZZ male, ZW female Birds Some fish Some reptiles Some insects (Butterflies/Moths) Some plants

  10. Sex Determination • Gender • Sex Linkage example: red-green coloblindness in humans 100% G, for all offspring 50% G daughters, 50% g sons Now, the sex of the parent that expresses the G trait matters; the transmission of this gene correlates with the sex of the offspring, because this trait and ‘sex’ are influenced by the same chromosome.

  11. Queen Victoria of England Her daughter Alice X-linked recessive traits are expressed in males (squares) more than females (circles), because females get a second X that may carry the dominant allele and hide the recessive.

More Related