Biology Questions and Answers
- What are lethal genes?
Lethal genes are genes having at least
one allele tgenotype of an individual, causes dehat, when present in the (^) ath.
There are recessive lethal alleles and
dominant lethal alleles. (genes having alleles that are There are alsodominant
when in heterozygin homozygosity, i.e., the dominanceosity but lethal when
related to the phenotype does not
correspond to the dominance rlethality.) elated to
- What are multiple alleles?
Is there dominance in multiple
alleles?
Multiple allwhich the same geles is the phenomenon inene has more than
two different alleles (in normal
mendelian itwo alleles). Obnheritance thviously the gene has onlyese alleles
combine in pairs to form the genotypes.
In multiple alleles relative dominance
among the alleles may eexample of multiple alleles isxist. A typical the
inheritance of the ABO blood group
system, in (A, B or O, or IA, IB and i). IA iswhich there are three alleles
dominant over i, which is recessive in
relation to thlack dominance e other IB allele. between themselves.IA and IB
Another example is thfur, conditioned by four different allele color of rabbites (^)
(C, Cch, Ch and c). In this case the
dominance relations> c (the symbol > m are C > Cch eans “dominates> Ch
over”).
- What are gene interactions?
What are the three main types
of gene interactions?
Gene interaction is thwhich a given phenotypicale phenomenon in trait is
conditionnot confuse with ed by two omultiple r more genes (doalleles in
which there is a single gene having
three or more alleles).
The three main types of gene
interactionepistasis and polygenic inheritance ( are: complementary genes,or
quantitative inheritance). - What are complementary
genes? Does this inheritance
pattern obey Mendel’s second
law?
Complemgenes that actentary g together to determinenes are different (^) e a
given phenotypical trait.
For exampltrait conditionee, considd by 2 compler a phenotypicalementary (^)
genes whose alleles are respectively X,
x, Y and y. PerformiF2 4 different phenotypical fng hybridization inorms are
obtained: XY (double dominant),
X_yy (recessive fodominar the second), xxY_nt for the first pair,
(recessive for the first pair, dominant
for the second) and xxyy (doublerecessive). This is what happens, for (^)
example, regarding the color of
budgerigar feathers, in which thdominant interaction results in greene double
feathers, the dominant for the first pair,
recessive foresults in yellow r the second interactionfeathers, the recessive (^)
for the first pair, dominant for the
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