Which chromosome is CyO on?
CyO
| Chromosome | Name of balancer chromosome | Dominant phenotype |
|---|---|---|
| X (First) | FM7 | Bar eye |
| 2 (Second) | SM5 or CyO | Curly wings |
| 3 (Tird) | TM3 or TM6 | Stubble bristles, Ser wings or Tb (Tubby) body |
Is TM3 homozygous lethal?
A line is said to be “double-balanced” if it is heterozygous for two different balancer chromosomes (for example, TM6,Tb/TM3,Ser) on one chromosome and a homozygous-lethal, heterozygous-visible mutant on the other, wild-type chromosome (for example, D/TM3,Ser).
What are balancer chromosomes used for?
Balancer chromosomes are an essential and powerful part of a fly geneticist’s toolbox. They are used to maintain deleterious mutations in stable stocks as well as to prevent recombination and follow chromosomes in genetic mating schemes.
What is a balancer Drosophila?
Balancer chromosomes are multiply inverted and rearranged chromosomes that are widely used in Drosophila genetics. First described nearly 100 years ago, balancers are used extensively in stock maintenance and complex crosses.
What is a balancer gene?
Genetic balancers are genetic constructs or chromosomal rearrangements that allow lethal or sterile mutations to be stably maintained in heterozygotes. In this chapter we use the term balancer primarily to refer to chromosomal duplications or rearrangements that suppress crossing over.
What causes Bar eyes in Drosophila?
When the chromosomes of males with bar eye are analyzed, a duplication in region 16A of the chromosome is detected. Another mutant of the eye shape is the double bar eye. These individuals have a second duplication of the same 16A region. This example shows how Drosophila polytene chromosomes can be used.
What does W * Mean in Drosophila?
white, abbreviated w, was the first sex-linked mutation discovered, found in the fruit fly Drosophila melanogaster. In 1910 Thomas Hunt Morgan and Lilian Vaughan Morgan collected a single male white-eyed mutant from a population of Drosophila melanogaster fruit flies, which usually have dark brick red compound eyes.
Are bar eyes dominant or recessive?
dominant
Bar is a dominant mutation causing premature arrest of the furrow, which results in the deep anterior nick in the adult eye.
What causes brown eyes in Drosophila?
In the eyes of Drosophila, the pigments responsible for eye color are produced by two biochemical pathways: the onmochrome pathway producing a brown pigment, and the pteridine pathway first passing through a pale blue then yellow pigment stages producing a bright red (scarlet) pigment called drosopterin.
Why is it called Robertsonian translocation?
Name. Robertsonian translocations are named after the American zoologist and cytogeneticist William Rees Brebner Robertson (1881–1941) who first described a Robertsonian translocation in grasshoppers in 1916. They are also called whole-arm translocations or centric-fusion translocations.
What is TT and TT?
Testcross is a cross of any genotype showing dominant phenotype with a recessive homozygote to determine the genotype of a dominant parent if it is a heterozygous- or homozygous-dominant. Being a hybrid Tt shows dominant phenotype and tt is the recessive parent; it is a test cross.