Lecture 1 Flashcards
What was Mendel’s First Law?
Law of Segregation - Every organism has two alleles for a trait that segregate randomly
What is an assumption made in pedigrees about individuals outside a family that marry into the family?
Assume wild type, unless otherwise indicated
What is an allele?
An allele is an alternative form of a gene resulting from mutation. There may be many mutant (disease causing) alleles or benign polymorphic variant alleles in the populations as a whole but each person has two alleles for every gene (except genes on the X chromosome in males)
What does the term hemizygous mean?
Hemizygous refers to males because they only have one X
chromosome. It refers to all the genes on the male X
chromosome. All of those alleles will be expressed no matter what.
If a disease is transferred from father to son, what can one assume?
The disease is not on the X chromosome, since the father must donate his Y chromosome to the son
What is genomic imprinting?
Genomic imprinting is an autosomal dominant phenomenon by which certain genes are expressed in a parent-of-origin specific manner. It is an inheritance pattern independent of classical Mendelian inheritance. Imprinted alleles are silenced such that genes are either expressed only from the non-imprinted allele inherited from the mother or in other instances from the non-imprinted allele inherited from the father.
What is horizontal gene transfer?
Horizontal gene transfer (HGT) refers to the transfer of genes between organisms in a manner other than traditional reproduction. Also termed lateral gene transfer (LGT), it contrasts with vertical transfer, the transmission of genes from the parental generation to offspring via sexual or asexual reproduction.
