Genetics of the snake star Astrobrachion constrictum (Ophiuroidea: Asteroschematidae) in Fiordland, New Zealand

This thesis was initiated to address two of the questions posed by Stewart's 1995 study on the biology of Astrobrachion constrictum; Is gene flow between fiords restricted in this ophiuroid species and are the colour morphs as different genetically as they are visually? Specimens of A. constrictum were collected from four sites within Doubtful Sound and one site in each of Nancy Sound, Preservation Inlet and Chalky Inlet. The genetics of these populations of the snake star were assessed using mitochondrial DNA and allozyme analysis. These results were analysed using G-test and AMOV A. Both G-test and AMOV A anlaysis showed that there was no significant genetic differentiation between populations within the same fiords (G[21] = 11.97; P > 0.9) (Fsc = -0.037, P > 0.05) or among fiords (G[21] = 23.32; P > 0.2) (FST = 0.013, P > 0.05). This result was unexpected as the Fiordland environment appears to present several barriers to dispersal, and genetic differentiation of Fiordland populations has been demonstrated in other echinoderm species. Genetic differences between the five colour morphs of A. constrictum were also assessed using mitochondrial DNA and allozyme analysis. G-test and AMOV A analysis of these results also showed no significant differences between colour morphs (G[28] = 13.88; P > 0.9) (F[ST] = -0.089, P > 0.05) indicating that they are conspecific. While studying the population genetics of the snake star two individuals were discovered which appeared to be heteroplasmic. Through the use of PCR cloning, SSCP and sequencing, the presence of heteroplasmy within these two individuals was demonstrated. This is the first reported case of heteroplasmy in an ophiuroid species and probably arose through paternal leakage. Cytochrome Oxidase I sequence obtained from the population analysis was also used in conjunction with sequences from Genbank to assess the phylogeny of echinoderms. Several studies have addressed echinoderm phylogeny over the past century but have failed to clarify the relationship between the echinozoa ( echinoids and holothuroids ), ophiuroids and asteroids. A relatively fast evolving gene was used in this study in an attempt to clarify this relationship. Of the nineteen trees generated with PAUP (Swofford, 1993), only one gave a topology indicating monophyly for all five classes. This was trimmed and compared with three previous hypotheses using the Kishino-Hasegawa test. Results from this showed no significant difference between hypotheses. This is probably due the large amount of noise introduced into the study through the use of a rapidly evolving gene

Genetic evidence of illegal trade in protected whales links Japan with the US and South Korea

We report on genetic identification of ‘whale meat’ purchased in sushi restaurants in Los Angeles, CA (USA) in October 2009 and in Seoul, South Korea in June and September 2009. Phylogenetic analyses of mtDNA cytochrome b sequences confirmed that the products included three species of whale currently killed in the controversial scientific whaling programme of Japan, but which are protected from international trade: the fin, sei and Antarctic minke. The DNA profile of the fin whale sold in Seoul established a match to products purchased previously in Japan in September 2007, confirming unauthorized trade between these two countries. Following species identification, these products were handed over to the appropriate national or local authorities for further investigation. The illegal trade of products from protected species of whales, presumably taken under a national permit for scientific research, is a timely reminder of the need for independent, transparent and robust monitoring of any future whaling

Low Diversity in theMitogenome of Sperm Whales Revealed by Next-Generation Sequencing

Large population sizes and global distributions generally associate with high mitochondrial DNA control region (CR) diversity. The sperm whale (Physeter macrocephalus) is an exception, showing low CR diversity relative to other cetaceans; however, diversity levels throughout the remainder of the sperm whale mitogenome are unknown. We sequenced 20 mitogenomes from 17 sperm whales representative of worldwide diversity using Next Generation Sequencing (NGS) technologies (Illumina GAIIx, Roche 454 GS Junior). Resequencing of three individuals with both NGS platforms and partial Sanger sequencing showed low discrepancy rates (454-Illumina: 0.0071%; Sanger-Illumina: 0.0034%; and Sanger-454: 0.0023%) confirming suitability of both NGS platforms for investigating low mitogenomic diversity. Using the 17 sperm whale mitogenomes in a phylogenetic reconstruction with 41 other species, including 11 new dolphin mitogenomes, we tested two hypotheses for the low CR diversity. First, the hypothesis that CR-specific constraints have reduced diversity solely in the CR was rejected as diversity was low throughout the mitogenome, not just in the CR [overall diversity pi]=0.096%; protein-coding 3rd codon =0.22%; CR =0.35%), and CR phylogenetic signal was congruent with protein-coding regions. Second, the hypothesis that slow substitution rates reduced diversity throughout the sperm whale mitogenome was rejected as sperm whales had significantly higher rates of CR evolution and no evidence of slow coding region evolution relative to other cetaceans. The estimated time to most recent common ancestor for sperm whale mitogenomes was 72,800 to 137,400 years ago (95% highest probability density interval), consistent with previous hypotheses of a bottleneck or selective sweep as likely causes of low mitogenome diversity.Keywords: Nucleotide diversity, Mitochondrial genome, Population genetics, Cetacean, Substitution rates, Physeter macrocephalus, mtDNA, Bayesian phylogenetic

What influences the worldwide genetic structure of sperm whales (Physeter macrocephalus)?

The interplay of natural selection and genetic drift, influenced by geographic isolation, mating systems and population size, determines patterns of genetic diversity within species. The sperm whale provides an interesting example of a long-lived species with few geographic barriers to dispersal. Worldwide mtDNA diversity is relatively low, but highly structured among geographic regions and social groups, attributed to female philopatry. However, it is unclear whether this female philopatry is due to geographic regions or social groups, or how this might vary on a worldwide scale. To answer these questions, we combined mtDNA information for 1091 previously published samples with 542 newly obtained DNA profiles (394-bp mtDNA, sex, 13 microsatellites) including the previously unsampled Indian Ocean, and social group information for 541 individuals. We found low mtDNA diversity (π = 0.430%) reflecting an expansion event <80 000 years bp, but strong differentiation by ocean, among regions within some oceans, and among social groups. In comparison, microsatellite differentiation was low at all levels, presumably due to male-mediated gene flow. A hierarchical amova showed that regions were important for explaining mtDNA variance in the Indian Ocean, but not Pacific, with social group sampling in the Atlantic too limited to include in analyses. Social groups were important in partitioning mtDNA and microsatellite variance within both oceans. Therefore, both geographic philopatry and social philopatry influence genetic structure in the sperm whale, but their relative importance differs by sex and ocean, reflecting breeding behaviour, geographic features and perhaps a more recent origin of sperm whales in the Pacific. By investigating the interplay of evolutionary forces operating at different temporal and geographic scales, we show that sperm whales are perhaps a unique example of a worldwide population expansion followed by rapid assortment due to female social organization.Genetic samples from the 'Voyage of the Odyssey' were collected under permit #0751-1614 from the US National Marine Fisheries Service

Population changes in a whale breeding ground revealed by citizen science noninvasive genetics

Historical exploitation, and a combination of current anthropogenic impacts, such as climate change and habitat degradation, impact the population dynamics of marine mammalian megafauna. Right whales (Eubalaena spp.) are large cetaceans recovering from hunting, whose reproductive and population growth rate appear to be impacted by climate change. We apply noninvasive genetic methods to monitor southern right whale (E. australis, SRW) and test the application of noninvasive genetics to minimise the observer effects on the population. Our aim is to describe population structure, and interdecadal and interannual changes to assess species status in the Great Acceleration period of Anthropocene. As a basis for population genetic analyses, we collected samples from sloughed skin during post-migration epidermal moult. Considering the exploration-exploitation dilemma, we collaborated with whale watching companies, as part of a citizen science approach and to reduce ad hoc logistic operations and biopsy equipment. We used mitochondrial and microsatellite data and population genetic tools. We report for the first time the genetic composition and differentiation of the Namibian portion of the range. Population genetic parameters suggest that South Africa hosts the largest population. This corresponds with higher estimates of current gene flow from Africa compared to older samples. We have observed considerable interannual variation in population density at the breeding ground and an interdecadal shift in genetic variability, evidenced by an increase in the point estimate inbreeding. Clustering analyses confirmed differentiation between the Atlantic and Indo-Pacific, presumably originating during the ice ages. We show that population monitoring of large whales, essential for their conservation management, is feasible using noninvasive sampling within non-scientific platforms. Observed patterns are concurrent to changes of movement ecology and decline in reproductive success of the South African population, probably reflecting a large-scale restructuring of pelagic marine food webs.Charles University Grant Agency, Czech Republic.https://www.elsevier.com/locate/geccoam2023Mammal Research InstituteZoology and Entomolog

mtDNA heteroplasmy gives rise to a new maternal lineage in North Pacific humpback whales

Heteroplasmy in the mitochondrial genome offers a rare opportunity to track the evolution of a newly arising maternal lineage in populations of non-model species. Here, we identified a previously unreported mitochondrial DNA haplotype while assembling an integrated database of DNA profiles and photo-identification records from humpback whales in southeastern Alaska (SEAK). The haplotype, referred to as A8, was shared by only two individuals, a mature female with her female calf, and differed by only a single base pair from a common haplotype in the North Pacific, referred to as A-. To investigate the origins of the A8 haplotype, we reviewed n = 1,089 electropherograms (including replicate samples) of n = 710 individuals with A- haplotypes from an existing collection. From this review, we found 20 individuals with clear evidence of heteroplasmy for A-/A8 (parental/derived) haplotypes. Of these, 15 were encountered in SEAK, four were encountered on the Hawaiian breeding ground (the primary migratory destination for whales in SEAK) and one was encountered in the northern Gulf of Alaska. We used genotype exclusion and likelihood to identify one of the heteroplasmic females as the likely mother of the A8 cow and grandmother of the A8 calf, establishing the inheritance and germ-line fixation of the new haplotype from the parental heteroplasmy. The mutation leading to this heteroplasmy and the fixation of the A8 haplotype provide an opportunity to document the population dynamics and regional fidelity of a newly arising maternal lineage in a population recovering from exploitation.Funding Support for this work was provided by a cooperative agreement between Oregon State University and the National Park Service (Pacific West Region Cooperative Ecosystems Study Unit Task Agreement #P12AC15004). Additional funding was provided by the Mamie Markham Research Award, Joan Crebbin Memorial Fellowship, Lylian Brucefield Reynolds Scholarship, Thomas G. Scott Grant Scholarship and the Hatfield Marine Science Center Student Organization Travel Grant. Acknowledgements We thank the SPLASH Steering Committee for access to haplotype information and sighting records. A special thanks to Charles Jurasz for his insight and foresight in documenting individual whales in southeastern Alaska. All research was conducted under appropriate permits issued by the US National Marine Fisheries Service, in accordance with the US Marine Mammal Protection Act and the US Endangered Species Act, including no. 14122 issued to J.M.S., nos. 945-1499-02 and 473-1700- 00 issued to the Glacier Bay National Park, and no. 675 issued to C.S.B.Ye

Local recruitment of humpback whales in Glacier Bay and Icy Strait, Alaska, over 30 years

We provide new information on the scale at which fidelity and recruitment underlie observed increases in humpback whale Megaptera novaeangliae populations.We provide new information on the scale at which fidelity and recruitment underlie observed increases in humpback whale Megaptera novaeangliae populations. We used photoidentification records and DNA profiles from whales in Glacier Bay and Icy Strait (GBIS), southeastern Alaska (SEAK) to investigate 3 sources of population increase over 33 yr (1973−2005): local GBIS recruitment, recruitment from elsewhere in SEAK, and immigration from outside SEAK. We defined 2 temporal strata for these longitudinal records: ‘founder’ individuals identified from 1973 to 1985 (n = 74; n = 46 with DNA profiles) and ‘contemporary’ individuals identified from 2004 to 2005 (n = 171; n = 118 with DNA profiles). To distinguish between local recruitment and recruitment from elsewhere in SEAK, we estimated the proportion of the contemporary stratum that was either a returning founder or descended from a founder female. After excluding 42 contemporary whales without a known mother or genotype to infer maternity, 73.6% of the contemporary stratum was confirmed or inferred through parentage analysis to be either a returning founder or a descendant of a founder mother. Of the 25 females with genotypes in the founder stratum, 24 (96%) were either represented in the contemporary stratum, had at least 1 descendant in the contemporary stratum, or both. We found no significant differences in microsatellite allele or mtDNA frequencies between the strata, suggesting little or no immigration from other feeding grounds. Our results highlight the importance of local habitat protection for a recovering species with culturally inherited migratory destinations.Ye

Tracking North Pacific Humpback Whales To Unravel Their Basin-Wide Movements

In 2014, Oregon State University (OSU) initiated a multi-year project to study humpback whale (Megaptera novaeangliae) migrations in the North Pacific Ocean using satellite tracking technology in combination with genetic and photo-identification (photo-ID) analyses. The study is highly relevant to management, given the need for new information arising from the recent separation of humpback whales into Distinct Population Segments (DPS) for listing under the US Endangered Species Act, including four DPSs in the North Pacific (“Western North Pacific”, “Hawaii”, “Mexico”, and “Central America”) with different conservation statuses. The project’s objective was to conduct a comprehensive characterization of humpback whale movements during breeding, migration, and feeding periods by tagging animals in both a feeding area (southeastern Alaska) and a breeding area (Hawaii). In order to obtain representative results, the sampling plan called for two field efforts at each site, with Pacific Life Foundation funding the southeastern Alaska portion of the project (2014 and 2015 seasons), and the Hawaii portion being cost-shared through a combination of sources including the Makana Aloha Foundation (2015 season) and the US Department of the Navy (2018 season). This final report provides the combined results and accomplishments from these efforts. Argos-based, fully implantable tags were deployed on 37 humpback whales in Seymour Canal and Frederick Sound, southeastern Alaska, in 2014 and 2015. Tracking periods ranged from 3.3 to 78.3 d (mean = 28.2 d, sd = 16.2 d), with distances traveled ranging from 73 to 6,503 km (mean = 2,010 km, sd = 1,649 km). The tracked locations for these animals ranged over 40 degrees of latitude, from Lynn Canal and Icy Strait (59°N) in southeastern Alaska to the southern tip of Hawaii Island (19°N) in the Hawaiian Archipelago. Genetic and photo-ID analyses revealed that two of the whales tagged in 2014 were re-tagged in 2015, providing a unique opportunity to compare movements between years for the same individuals. For one of these animals the movements and their timing were similar between years, as it moved from Seymour Canal into Frederick Sound with a difference of 4 d between years. However, early failure of the tag in 2014 (after 6.2 d) prevented a longer comparison. In contrast, the movements of the second animal within southeastern Alaska were similar but the timing was very different between the two years, despite a similar tracking period (21.9 d in 2014 versus 19.1 d in 2015). In 2014 this animal spent a substantial amount of time in Seymour Canal (17 d) before moving into Stephens Passage for the remainder of its tracking period, while in 2015 the animal moved into Stephens Passage soon after tagging and only for a brief period before it moved into Frederick Sound, from where it initiated the migration toward Hawaii. Differences in timing notwithstanding, the similarities in the tracks between years for both animals provided some evidence of route fidelity, as has been recently shown for several species of migratory marine animals. Twenty of the whales tagged in southeastern Alaska began their winter migration to a low-latitude breeding area, with start dates ranging from 19 November to 6 January. Three of these whales were tracked to breeding areas, two to Hawaii and one to the Mexican mainland. Another 16 whales were headed in the direction of Hawaii and one in the direction of Mexico when their tags quit. The duration and distance spent on migration for the three animals that reached a breeding area ranged from 29 to 46 d and from 4,200 to 4,700 km, respectively. The two animals that arrived in Hawaii entered the archipelago at Hawaii Island. Forty-five tags were deployed on humpback whales off Maui, Hawaii, in 2015 and 2018. Two of these tags provided no locations. Tracking periods for the remaining 43 whales ranged from 0.1 to 147.2 d (mean = 20.8 d, sd = 29.0 d), with distances ranging from 13 to 11,302 km (mean = 1,217 km, sd = 2,348 km). The tracked locations for these animals ranged over 43 degrees of latitude, from the south coast of Maui (21°N) to the Bering Sea (64°N). While in Hawaiian waters, the majority of locations were in the Maui Nui region (the waters between the islands of Maui, Lanai, Molokai and Kahoolawe), during both in 2015 and 2018. Penguin Bank was another area heavily frequented by the tagged whales. Most tagged whales moved in a predominant northwesterly direction after tagging, with animals leaving Maui headed for Lanai, Molokai, and/or Penguin Bank. Several whales were also tracked to Oahu, and one whale was further tracked to both Kauai and Niihau. Only one whale was tracked southeast to Hawaii Island in 2015, but other tagging studies have documented eastward movements to Oahu, Penguin Bank, and Maui Nui, so it is apparent that whales may move extensively between islands, both in westerly and easterly directions. Nine of the whales tagged in Hawaii began their migration to a high-latitude feeding area, with departure dates ranging from 29 January to 11 April. Four of these whales were tracked to feeding areas, three to northern British Columbia and one to the eastern Aleutian Islands. Another four whales were headed on a northeasterly trajectory toward northern British Columbia and three more on a northerly or northwesterly trajectory toward destinations in the Aleutian Island chain when their tags quit. The three whales that were tracked to northern British Columbia arrived in the Haida Gwaii Archipelago after having spent 30-44 d and 4,300-5,000 km on migration. The animal that migrated north to the eastern Aleutians arrived at an area approximately 200 km south of Unimak Pass, 28 d and 3,775 km after departing Hawaii. These results, together with those obtained from animals tagged in southeastern Alaska that migrated to a breeding area (Hawaii or Mexico), provide evidence that the travel time and distance covered by humpback whales while on migration across the North Pacific Basin can vary widely, with overall ranges of 28-46 d and 3,775-5,000 km, respectively. A 50-km buffer zone around southeastern Alaska and Hawaii was used for purposes of characterizing whale movement speeds and residence times in the feeding and breeding areas (inside the buffer zones), as well as during migration (outside the buffer zones). Residence time was computed as the time period from tag deployment to when a whale crossed the buffer zone boundary as it departed on migration. Residence time in southeastern Alaska in late fall was estimated for 20 whales, ranging from 4.4 to 49.1 d (mean = 17.3 d), although additional information from earlier tagging studies indicated that individual humpback whales may use this feeding area for periods of up to four to five months. In contrast, residence time in Hawaii was estimated for nine whales, ranging from 3.3 to 23.2 d (mean = 14.8 d), consistent with earlier photo-ID and telemetry studies and lending support to the notion that that there is a rapid turnover of individuals in this breeding area during the winter season. In any case, overall true residence time in these areas is likely longer than the minimum values we report based on satellite telemetry, as we cannot know the time a whale had spent in an area prior to tagging. Movement speeds during the different phases of the migration (feeding, breeding, migrating) were calculated based on the portions of the tracks that occurred inside or outside the 50-km buffer zones. Whales tagged in southeastern Alaska moved at a mean speed of 1.01 km/h (median = 0.47 km/h, sd = 1.28 km/h) while in the southeastern Alaska feeding area; 5.51 km/h (median = 5.63 km/h, sd = 1.98 km/h) while migrating; and 1.49 km/h (median = 1.01 km/h, sd = 1.36 km/h) once they arrived in the Hawaii breeding area. Whales tagged in Hawaii moved at a mean speed of 1.36 km/h (median = 1.00 km/h, sd = 1.21 km/h) while in the Hawaii breeding area; 4.44 km/h (median = 4.32 km/h, sd = 2.18 km/h) while migrating; and 2.00 km/h (median = 1.53 km/h, sd = 1.53 km/h) once they arrived in the southeastern Alaska feeding area. These results showed that whales moved much slower while in the feeding and breeding areas than while migrating, and that travel speed from the feeding to the breeding areas was somewhat faster than from the breeding to the feeding areas. Biopsy samples were collected from 27 of the whales tagged in southeastern Alaska in 2014 and 2015, and from 39 of the whales tagged in Hawaii in 2015 and 2018. These 66 samples were identified by a unique multi-locus genotype of at least 14 microsatellite loci, which indicated they represented 64 unique individuals (after accounting for the two animals that were re-tagged). The 25 individuals tagged in southeastern Alaska represented 14 females and 11 males. The 39 individuals tagged in Hawaii represented four females and 35 males. The DNA profiles of the 64 individuals were compared to a reference database of 1,805 individuals sampled from 2004 to 2006 in the North Pacific by the program SPLASH, which revealed nine matches (i.e., genotype recaptures). Of these, six matches were recaptures within an area (four within southeastern Alaska and two within Hawaii) and three were recaptures between whales tagged in Hawaii and sampled previously on feeding areas in either northern British Columbia (n = 2) or southeastern Alaska (n = 1). Mitochondrial deoxyribonucleic acid (mtDNA) sequences of the 64 individuals resolved seven haplotypes for the consensus region of 500 base-pairs. All seven haplotypes had been previously described for North Pacific humpback whales by SPLASH, but only two occurred in the southeastern Alaska samples while all seven occurred in the Hawaii samples, supporting earlier results indicating a greater haplotypic diversity in the Hawaii breeding area than in the southeastern Alaska feeding area. Further, pairwise tests of differentiation between the tagging areas and the 18 SPLASH regional strata were consistent with those reported in that study, supporting our current understanding of humpback whale population structure, migratory destinations, and site fidelity in the North Pacific. Photo-IDs (fluke photographs) were obtained from 30 whales tagged in southeastern Alaska and from 24 whales tagged in Hawaii. Comparisons with the online Happywhale photo-ID database as well as with OSU’s own ID catalog revealed matches for 25 of the tagged whales (18 from southeastern Alaska and seven from Hawaii). Thirty-five percent of the tagged whales with an ID were found in Happywhale and 13 percent in OSU’s catalog. Most matches (19 of 25) were made within the same area in which the whale was tagged, with time spans between sightings of up to 14 years. Two whales tagged in southeastern Alaska in 2014 each had only one photo-ID match in a different area than the one in which they were tagged. Both had been previously photographed in Hawaii, one in 1997 (17 years apart) and in 2004 (10 years apart). The remaining four resighted tagged whales had both within- and between-area matches. Three of these latter whales were tagged in southeastern Alaska, with two of them matching sightings in Hawaii (1987 and 2019, respectively), and the third one being resighted in central California on two consecutive years (2017 and 2018). The fourth whale was tagged in Hawaii and matched sightings over six consecutive years (2013-2018) in southern British Columbia/northern Washington. An additional 26 matches were found in Happywhale from among 149 fluke photographs of untagged whales collected by OSU in Hawaii. Of these, 13 matches were made within Hawaii (with a maximum time span between sightings of 21 years); nine matches were made between Hawaii and different parts of Alaska, including southeastern Alaska, Kodiak Island, Cook Inlet, and the Shumagin Islands; four matches were made between Hawaii and Washington State and Vancouver Island, British Columbia; and one match was made between Hawaii and the Chukchi Sea, near Kolyuchin Island, northeastern Russia. Through the combined use of satellite tagging, genetics, and photo-ID, we characterized the patterns of humpback whale occupation in both a breeding and a feeding area in the North Pacific Ocean, as well as the long-distance migratory movements that these animals undertake seasonally between these areas. The results of this study revealed the complex migratory linkages between Hawaii and the high-latitude feeding areas with unprecedented detail. Genotype and photo-ID recaptures of multiple individuals between migratory destinations supported previously known strong connections between breeding and feeding areas (e.g., Hawaii and southeastern Alaska/northern British Columbia, and Hawaii and Washington/southern British Columbia). Satellite tracking also revealed the movements and migratory connections between Hawaii and feeding areas in the Aleutian Islands and the Bering Sea, while photo-ID recaptures demonstrated additional connections between Hawaii and feeding areas in the northern Gulf of Alaska (Shumagin Islands, Kodiak Island, Cook Inlet) and the Chukchi Sea. Additional years of sampling during different parts of the reproductive season and in other parts of the main Hawaiian islands (e.g., Kauai and Hawaii), as well as in the northwestern Hawaiian Islands, would provide valuable information to address outstanding questions about the humpback whale DPS using this extensive breeding area, as well as its broader connections to remote feeding areas throughout the North Pacific Basin, most of which are poorly known. Also, while the majority of whales tracked from southeastern Alaska showed a strong connection to the Hawaii breeding area, a small proportion of these animals demonstrated a connection to the Mexican mainland breeding area, indicating some mixing of the Hawaii and Mexico DPSs in the southeastern Alaska feeding area. These animals are of particular interest, as in their transit along the western coast of North America they overlap with animals from the Central America DPS, which forages off California and Oregon. Further tagging work to better understand the patterns of habitat use and the extent of the overlap between the Mexico and Central America DPSs in this region would greatly help current needs to improve how animals are assigned to DPS for management purposes in the context of relative exposure to anthropogenic activities, given their different conservation statuses

Resurrection of Mesoplodon hotaula Deraniyagala 1963: A new species of beaked whale in the tropical Indo-Pacific

We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans.Keywords: Species delimitation, Mesoplodon, Nuclear introns, Taxonomy, Y-chromosome, mtDNA, Morphology, Speciation, Beaked whal

Multifactorial Analysis of Differences Between Sporadic Breast Cancers and Cancers Involving BRCA1 and BRCA2 Mutations

Background: We have previously demonstrated that breast cancers associated with inherited BRCA1 and BRCA2 gene mutations differ from each other in their histopathologic appearances and that each of these types differs from breast cancers in patients unselected for family history (i.e., sporadic cancers). We have now conducted a more detailed examination of cytologic and architectural features of these tumors. Methods: Specimens of tumor tissue (5-µm-thick sections) were examined independently by two pathologists, who were unaware of the case or control subject status, for the presence of cell mitosis, lymphocytic infiltration, continuous pushing margins, and solid sheets of cancer cells; cell nuclei, cell nucleoli, cell necrosis, and cell borders were also evaluated. The resulting data were combined with previously available information on tumor type and tumor grade and further evaluated by multifactorial analysis. All statistical tests are two-sided. Results: Cancers associated with BRCA1 mutations exhibited higher mitotic counts (P = .001), a greater proportion of the tumor with a continuous pushing margin (P<.0001), and more lymphocytic infiltration (P = .002) than sporadic (i.e., control) cancers. Cancers associated with BRCA2 mutations exhibited a higher score for tubule formation (fewer tubules) (P = .0002), a higher proportion of the tumor perimeter with a continuous pushing margin (P<.0001), and a lower mitotic count (P = .003) than control cancers. Conclusions: Our study has identified key features of the histologic phenotypes of breast cancers in carriers of mutant BRCA1 and BRCA2 genes. This information may improve the classification of breast cancers in individuals with a family history of the disease and may ultimately aid in the clinical management of patients. [J Natl Cancer Inst 1998;90:1138-45