A very detailed study of color and coat of Syrian Hamsters - used by the Agriscience class at Santa Rita High School during the ongoing genetic breeding program.
2. Standards Addressed: 15.0 Animal Growth and Production 15.3 Reproduction 15.4 Biotechnology – 16.0 Using Scientific Processes to Analyze Data 16.1 Scientific Method 16.2, 16.3, 16.4 Scientific Research 16.6, 16.8 Communicating Results 17.0 Relationships Within Living Systems 17.2 Heredity 18.0 Bioethical Issues 18.3 Animal production
3. Objectives: In a Laboratory Environment Students will be able to: 1- Use the scientific method to hypothesize, predict implement and report conclusions 2 – Illustrate patterns of inheritance using the principles of Mendel’s genetic theory 3 – Demonstrate respectful, and appropriate treatment of lab animals
4. Process: Using Syrian Hamsters students will identify phenotype of animal. Through multi generation breeding the genotype will be determined As genotype becomes established, predictions regarding future generations are made, tested, and results reported
5. Why Use Syrian Hamsters? 1 – A friendly, affordable, easily available animal 2 – Rapid maturation of pups 3 – Easily bred – short estrous cycle – 4 days 4 – Gestation period 16 days 5 – Established coat color, coat type, and coat markings 4 – Monohybrid and dihybrid crosses visible
9. Basic Genetic Information: Hamsters have 44 chromosomes Ovaries carry 21 autosomes and an X gamete Sperm carry 21 autosomes and an X or Y gamete Syrian hamster Karyotype courtesy of Knud Christensen, Ph.D., The Royal Veterinary Agricultural University, Denmark
10. Step 1: figure out the hamster's phenotype, and write a preliminary genotype. A few quick examples. ("_" stands for "unknown.") Banded Longhair Red Eyed Cream Ba_eellpp Satin Cinnamon Tortoiseshell ppSasaToto Dominant Spot Yellow Black male aaDsdsToY Rex Smoke Pearl female dgdgrxrxToTo Chocolate (Sable) Roan bbeeU_ Whwh Recessive Dappled Umbrous Golden rdrdU_
11. Expanding the Genotype More information about the hamster's genotype can be gathered by looking at its parents, siblings and offspring
12. Breeding an animal can provide more data about its genetic make-up. It is especially useful as a tool to confirm suspicions of heterozygosity. For any trait that may be heterozygous, breed to an animal that is homozygous recessive.
13. Appropriate breeding can help sort out confusing colors. For example this helps with the Greys, especially if the Grey is in combination (for instance, in the Grey Sables or Black Eyed Ivories). Breeding to any hamster without grey in its pedigree will give a good indication of the genotype.
14. There are eleven basic colors in Syrians. Ten (excluding Golden, which is the “wild type”) are determined by a single gene pair .
15. It can be hard to determine color because coat types and coat patterns also influence appearance.
16. Golden – wild color combination – where it all started “ Ticking” of coat And, the fur is often different close to the skin, from what is seen on top -
18. Color Genotype Description Golden ++ Rich dark mahogany heavy black ticking OR Light fawny gold Golden is the agouti, or wild code. It must carry all color genes possible, so would look like this: AA BB baba CC DgDg dsds EE FdFd LL lglg PP RdRd RuRu RxRx SS sasa sgsg toto uu whwh
29. Color Tortoiseshell (females only) TotoBaba, TotoBaBa, or TotoDsds sex-linked bi-colored or tricolor animal - a balanced pattern of colored, yellow and white patches (sometimes black) Genotype Description
42. Piebald ss Similar to dominant spot, but has colored patches also on belly
43. Color Tortoiseshell (females only) TotoBaba, TotoBaBa, or TotoDsds sex-linked bi-colored or tricolor animal - a balanced pattern of colored, yellow and white patches (sometimes black) Genotype Description
44. The yellow patches in Tortoiseshell are modified according to base color – Cinnamon becomes honey – Dark Grey becomes pearl – Lilac becomes lilac pearl Remember – this is a sex linked trait – only in females!
45. There are two main breeding techniques - selection and crossing. Selection is the careful choosing of individuals for mating, allowing only the best to become parents of the next generation.
46. Crossing , is the pairing of the selected individuals so that the best offspring possible can be produced.
47. Inbreeding involves crosses of first degree relatives. This is done to concentrate desirable genes. Unfortunately, it will also concentrate undesirable genes so it must be accompanied by rigorous selection and care.
48. Backcross (offspring bred to one of its parents) Do with care and only 1 generation Sibling cross (brother bred to sister – the most unsafe – only unusual circumstances (verify genetics_
49. Linebreeding is the pairing of more distantly related animals. Cousin to cousin – Aunt to nephew, uncle to niece -considered fairly safe
50. Outcrossing is the breeding of totally unrelated animals. Done when 2 exceptional, unrelated animals exist. Very safe.
51. Lethality Lethal genes result in death in utero or Shortly after birth. Lg (Light, or Lethal, Grey) and Ds (Dominant Spot) are lethal in homozygotes. In a monohybrid cross (e.g., Lglg x Lglg) 1/4 of the embryos are likely to be homozygous dominant and will not survive. The litter is then three fourths as large as it would have been and has the remaining genotype (and phenotype) ratio of 2:1. Since the surviving hamsters are healthy, the only disadvantage of these matings is smaller litters.
52. Mating two hamsters that are Roan or White Bellied (both Whwh) gives litters in which 1/4 of the babies can be expected to be Eyeless Whites (WhWh). Eyeless Whites typically have a shortened lifespan of six to twelve months.
54. Produced for: Santa Rita High School Agriscience Program By: Catherine Patterson, Instructor Special Thanks To: River Road Hamstry and the many owners and breeders of Hamsters who placed information on the web.