Traits that influence longevity in mice: a second look.

Abstract Analysis of genetic interactions in the F2 of an intercross of (C57BL/6 x DBA/2) F1J revealed influences of genetic factors on life span. Females lived longer than males. Dilute brown females died sooner than females of other colors. H-2b/H-2b males died sooner than H-2b/H-2d or H-2d/H-2d males, except that among dilute brown males those of typeH-2b/H-2d died sooner. Cluster analysis suggested that male and female genotypes each fall into two groups, with female dilute brown mice having shorter lives than other females, and male H-2b/H-2b mice except dilute brown and dilute brown H-2b/H-2d mice having shorter lives than other males. The association of heterozygosity with life span was clearer in females than in males, yet the longest-lived female genotype was homozygous H-2d/H-2d, of dominant Black phenotype at the Brown locus of chromosome 4, and homozygous dd at the Dilute locus of chromosome 9. The shortest-lived females were dilute brown H-2b/H-2b. The longest-lived and shortest-lived male genotypes were dilute brown H-2d/H-2d and dilute brown H-2b/H-2d, respectively. Although histological findings at postmortem differed between the sexes, there was no association of particular disorders with other genetic markers. The importance of H-2 in males was confirmed, but the allelic effects were perturbed, possibly by the absence of Sendai infection in this experiment. Overall our studies suggest that genetic influences on life span involve interactions between loci, and allelic interactions may change with viral infections or other environmental factors.

Download Full-text

TRAITS THAT INFLUENCE LONGEVITY IN MICE

Genetics ◽

10.1093/genetics/108.4.999 ◽

1984 ◽

Vol 108 (4) ◽

pp. 999-1011

Author(s):

Edmond J Yunis ◽

Ada L M Watson ◽

Rebecca S Gelman ◽

Sherrill J Sylvia ◽

Roderick Bronson ◽

...

Keyword(s):

Life Span ◽

Causes Of Death ◽

Coat Color ◽

Genetic Interactions ◽

Chromosome 9 ◽

Chromosome 17 ◽

Chromosome 4 ◽

Limited Extent ◽

Month Of Birth ◽

Genetic And Environmental Factors

ABSTRACT Analysis of genetic interactions in the segregating backcross [(C57BL/6 x DBA/2)F1 x DBA/2] mice revealed influences of genetic and environmental factors on life span. Using determinants of coat color (brown locus of chromosome 4 and dilute locus of chromosome 9), serologically determined H-2 antigens (chromosome 17) and sex as genetic markers, we studied the effects of these genes on longevity. The results suggested that genes in the brown locus (b) segment of chromosome 4, genes in a segment of the sex chromosomes and, to a more limited extent, genes in the segment of chromosome 17 which contains the H-2 haplotype all influenced longevity. The coat color (b locus) segment of chromosome 4 was associated with life span predominantly in females, whereas the chromosome 17 (H-2 haplotype) segment was associated with longer life primarily in males. The dilute locus d segment on chromosome 9 did not affect life span. Longevity appears to be influenced by interactions between genes in the chromosomal segment carrying H-2, those in the b segment, gender and the month of birth. Greater heterozygosity at the loci studied was associated with longer life span. Histopathological findings on mice that died at or after 28 months of age were comparable for all genetic combinations except that there was an increased frequency of lymphoma in females and an increased frequency of amyloidosis in males. Our analysis emphasizes the need for comprehensive studies of aging and longevity that would simultaneously determine the effects of several genetic regions and their interactions with the environment with respect to possible causes of death.

Download Full-text

Rate of loss of radioiron from mouse and man

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1960.198.4.784 ◽

1960 ◽

Vol 198 (4) ◽

pp. 784-786 ◽

Cited By ~ 7

Author(s):

John D. Bonnet ◽

Alan L. Orvis ◽

Albert B. Hagedorn ◽

Charles A. Owen

Keyword(s):

Life Span ◽

Half Life ◽

Whole Body ◽

Entire Body ◽

Rapid Loss ◽

Male And Female ◽

Female Mice ◽

Steady Rate ◽

Normal Man ◽

The Difference

Forty-two male and female mice, 8 weeks old, were given radioiron (Fe59) in doses of 0.006–0.1 µc, containing 0.013–0.17 µg of iron, by intraperitoneal or intravenous routes. Assays of the radioactivity of the whole body revealed an initial rapid loss of Fe59 (15–20%) lasting about 6 days. Thereafter the Fe59 left the mice at a steady rate of 0.39%/day (half-life 180 days). One 34-year-old normal man was given 10.6 µc of Fe59, containing 8.2 µg of iron, intravenously. Based on counts from the entire body, the biologic rate of loss of the Fe59 was about 0.14%/day (half-life 500 days), and there was little or no initial loss such as occurred in the mouse. The Fe59 in the circulating erythrocytes was essentially unchanged for the first 3 months. It then fell to a new level of about 90% of the previous one; the mid-point of the fall was about 120 days after the administration of the radioiron. The difference in the rates of loss of radioiron from mice and man seems to be related primarily to the life span of the circulating red cells.

Download Full-text

Genome-wide study on the polysomic genetic factors conferring plasticity of flower sexuality in hexaploid persimmon

DNA Research ◽

10.1093/dnares/dsaa012 ◽

2020 ◽

Vol 27 (3) ◽

Author(s):

Kanae Masuda ◽

Eiji Yamamoto ◽

Kenta Shirasawa ◽

Noriyuki Onoue ◽

Atsushi Kono ◽

...

Keyword(s):

Genetic Factors ◽

Diospyros Kaki ◽

Dependent Manner ◽

Male And Female ◽

Association Analyses ◽

Genome Wide ◽

Allele Dosage ◽

Partial Inactivation ◽

In Cis ◽

Segregating Population

Abstract Sexuality is one of the fundamental mechanisms that work towards maintaining genetic diversity within a species. In diploid persimmons (Diospyros spp.), separated sexuality, the presence of separate male and female individuals (dioecy), is controlled by the Y chromosome-encoded small-RNA gene, OGI. On the other hand, sexuality in hexaploid Oriental persimmon (Diospyros kaki) is more plastic, with OGI-bearing genetically male individuals, able to produce both male and female flowers (monoecy). This is thought to be linked to the partial inactivation of OGI by a retrotransposon insertion, resulting in DNA methylation of the OGI promoter region. To identify the genetic factors regulating branch sexual conversion, genome-wide correlation/association analyses were conducted using ddRAD-Seq data from an F1 segregating population, and using both quantitative and diploidized genotypes, respectively. We found that allelic ratio at the Y-chromosomal region, including OGI, was correlated with male conversion based on quantitative genotypes, suggesting that OGI can be activated in cis in a dosage-dependent manner. Genome-wide association analysis based on diploidized genotypes, normalized for the effect of OGI allele dosage, detected three fundamental loci associated with male conversion. These loci underlie candidate genes, which could potentially act epigenetically for the activation of OGI expression.

Download Full-text

A computational study of autoimmune disease model

Asian-European Journal of Mathematics ◽

10.1142/s1793557120501697 ◽

2020 ◽

Vol 13 (08) ◽

pp. 2050169

Author(s):

Iveta Nikolova ◽

Anka Markovska ◽

Mikhail Kolev

Keyword(s):

Mathematical Model ◽

Autoimmune Disease ◽

Qualitative Analysis ◽

Numerical Experiments ◽

Genetic Factors ◽

Viral Infections ◽

Computational Study ◽

Disease Model ◽

Point Of View ◽

Economic Conditions

Nowadays autoimmune diseases are widely distributed. More than 80 illnesses are included into this group of conditions. Their causes are not clear exactly, but it is believed that among them are genetic factors, viral infections, socio-economic conditions, etc. We propose a new mathematical model describing a general autoimmune disease in order to analyze some mechanisms of autoimmune disorders. The model is a system of ordinary differential equations. We perform preliminary qualitative analysis of the model as well as propose an algorithm for numerical simulations. Some results of our numerical experiments are presented and commented from a biological point of view.

Download Full-text

CHROMOSOME BANDING HOMOLOGIES OF A TANDEM FUSION IN RIVER, SWAMP, AND CROSSBRED BUFFALOES (BUBALUS BUBALIS)

Canadian Journal of Genetics and Cytology ◽

10.1139/g82-070 ◽

1982 ◽

Vol 24 (6) ◽

pp. 667-673 ◽

Cited By ~ 16

Author(s):

T. A. Bongso ◽

M. Hilmi

Keyword(s):

First Generation ◽

Bubalus Bubalis ◽

Chromosome 9 ◽

Chromosome 4 ◽

Centromere Region ◽

Hybrid Female ◽

Banding Patterns ◽

C Banding ◽

Tandem Fusion ◽

Y Chromosomes

The chromosomes of the Murrah (River), Swamp (Malaysian kerbau), F1 hybrid (Murrah × Swamp) and first generation backcross (F1 hybrid female × Murrah male) buffaloes (Bubalus bubalis L.) were studied using Giemsa (G) and centromeric (C) banding techniques. The diploid chromosome number for the Murrah was 2n = 50, Swamp 2n = 48, F1 hybrid 2n = 49 and two backcross animals had 2n = 49 and 2n = 50, respectively. The largest two metacentric chromosomes of the Swamp resulted from a tandem fusion between the two chromosomes 4p and 9, respectively, of the Murrah karyotype. The F1 hybrid (2n = 49) and one of the backcrosses (2n = 49) had karyotypes intermediate to the Murrah and Swamp parents. The C banding patterns were useful in identifying the X and Y chromosomes of the buffalo and demonstrated that a major portion of the centromere region of chromosome 9 was not incorporated into chromosome 4 during the tandem fusion.

Download Full-text