Sex biases in the mutation rate. Evidence was initially found in the Zebra finch. Incipient speciation by sexual isolation in Drosophila : concurrent evolution at multiple loci.
However, a female egg cell may carry only an X sex chromosome. At least a dozen different disorders are now known to result from triplet repeat expansions in the human genomeand these fall into two groups: 1 those that involve a polyglutamine tract within the encoded protein product that becomes longer upon expansion of a triplet repeat, an example of which is Huntington diseaseand 2 those that have unstable triplet repeats in noncoding portions of the gene that, upon expansion, interfere with appropriate expression of the gene product, an example of which is fragile-X syndrome see photograph.
Articles from Britannica Encyclopedias for elementary and high school students. Sexsmith, Ron. These corresponding locations are referred to as loci.
In an X-linked cross, the genotypes of F 1 and F 2 offspring depend on whether the recessive trait was expressed by the male or the female in the P 1 generation. Leave a Reply Cancel reply Your email address will not be published. Robotics Robot teachers uses, advantages and disadvantages 20 Jun, A person with color blindness has difficulty seeing color differences.
Univ Calif Publ Zool 58 : 1— Genetic analysis of cuticular hydrocarbons and their effect on courtship in Drosophila virilis and D. The chromosomes of neighboring pairs are partially homologous, such that a chain is formed during mitosis.