Chapter 7-chromosomes And Phenotype Flashcards
What is the biggest factor in gene expression?
Whether the gene is located on an autosome or on a sex chromosome
Are genetic disorders and sex linked diseases dominant or recessive? What is a carrier of a genetic disorder or sex linked disease? Do carriers show the disease?
Recessive. A carrier is someone who has one recessive (disorder) allele and one dominant (normal allele). Carriers do not show the disease but can pass it on
What is X chromosome inactivation?
A process in female mammals in which one of the x chromosomes is randomly turned off in each cell
What is an epistatic gene? How many genes are on the X chromosome? Y chromosome?
A gene that effects only one specific allele or gene in a certain genotype. There are 1527 genes on the X and 23 on the Y
What is incomplete dominance? Whats an example? How can you put incomplete dominance in your own words?
When neither allele in a heterozygous phenotype is completely dominant nor completely recessive. When a homozygous red plant crosses with a homozygous white plant and the offspring have pink flowers. SOME HETEROZYGOUS GENOTYPES RESULT IN THEIR OWN PHENOTYPE RATHER THAN EXPRESSING THE DOMINANT ALLELE
What is co-dominance? Give an example
When both traits are fully and separately expressed. If a homo red and a homo white plant crossed, their offspring would have some areas of red, and some of white
What is the Genotype for type A blood? B? AB? O?
A-IAIA or Iai
B-IBIB or IBi
AB-IAIB
O-ii
What are polygenic traits? What is an example?
Traits that are produced by 2 or more genes? Ex. Eye color is expressed through 5 or more different genes
What is the epistatic gene?
The epistatic gene can interfere with the expression of others genes, meaning its the most powerful of the other genes and can overrule their expression
What is sexual dimorphism? Give an example?
The two sexes of the same species exhibit different characteristic beyond their sexual organs? Ex. In birds, the females are larger and have brighter colors
What are linked genes? What did the scientist that discovered genetic linkage conclude about meiosis?
Genes that are inherited together and on the same chromosome. The scientist concluded that chromosomes exchange homologous genes during meiosis
Can males be carriers of sex linked disorders? Why or why not?
Males cannot be carriers because they do not have a second X chromosome to mask the X chromosome with the disorder.
What is a pedigree? What is a Karyotype?
Pedigree-A chart that is used to help trace phenotypes and genotypes in a family to determine whether people carry certain alleles
Karyotype-a picture of all the chromosomes in a cell
What genotype is required for a female to have color blindness? Males?
Females-XmXm
Males-XmY
